Merge branch develop of github.com:/EllisLab/CodeIgniter into session

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diff --git a/user_guide_src/source/overview/appflow.rst b/user_guide_src/source/overview/appflow.rst
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+######################
+Application Flow Chart
+######################
+
+The following graphic illustrates how data flows throughout the system:
+
+|CodeIgniter application flow|
+
+#. The index.php serves as the front controller, initializing the base
+   resources needed to run CodeIgniter.
+#. The Router examines the HTTP request to determine what should be done
+   with it.
+#. If a cache file exists, it is sent directly to the browser, bypassing
+   the normal system execution.
+#. Security. Before the application controller is loaded, the HTTP
+   request and any user submitted data is filtered for security.
+#. The Controller loads the model, core libraries, helpers, and any
+   other resources needed to process the specific request.
+#. The finalized View is rendered then sent to the web browser to be
+   seen. If caching is enabled, the view is cached first so that on
+   subsequent requests it can be served.
+
+.. |CodeIgniter application flow| image:: ../images/appflowchart.gif
diff --git a/user_guide_src/source/overview/at_a_glance.rst b/user_guide_src/source/overview/at_a_glance.rst
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+#######################
+CodeIgniter at a Glance
+#######################
+
+CodeIgniter is an Application Framework
+=======================================
+
+CodeIgniter is a toolkit for people who build web applications using
+PHP. Its goal is to enable you to develop projects much faster than you
+could if you were writing code from scratch, by providing a rich set of
+libraries for commonly needed tasks, as well as a simple interface and
+logical structure to access these libraries. CodeIgniter lets you
+creatively focus on your project by minimizing the amount of code needed
+for a given task.
+
+CodeIgniter is Free
+===================
+
+CodeIgniter is licensed under an Apache/BSD-style open source license so
+you can use it however you please. For more information please read the
+:doc:`license agreement <../license>`.
+
+CodeIgniter is Light Weight
+===========================
+
+Truly light weight. The core system requires only a few very small
+libraries. This is in stark contrast to many frameworks that require
+significantly more resources. Additional libraries are loaded
+dynamically upon request, based on your needs for a given process, so
+the base system is very lean and quite fast.
+
+CodeIgniter is Fast
+===================
+
+Really fast. We challenge you to find a framework that has better
+performance than CodeIgniter.
+
+CodeIgniter Uses M-V-C
+======================
+
+CodeIgniter uses the Model-View-Controller approach, which allows great
+separation between logic and presentation. This is particularly good for
+projects in which designers are working with your template files, as the
+code these files contain will be minimized. We describe MVC in more
+detail on its own page.
+
+CodeIgniter Generates Clean URLs
+================================
+
+The URLs generated by CodeIgniter are clean and search-engine friendly.
+Rather than using the standard "query string" approach to URLs that is
+synonymous with dynamic systems, CodeIgniter uses a segment-based
+approach::
+
+	example.com/news/article/345
+
+Note: By default the index.php file is included in the URL but it can be
+removed using a simple .htaccess file.
+
+CodeIgniter Packs a Punch
+=========================
+
+CodeIgniter comes with full-range of libraries that enable the most
+commonly needed web development tasks, like accessing a database,
+sending email, validating form data, maintaining sessions, manipulating
+images, working with XML-RPC data and much more.
+
+CodeIgniter is Extensible
+=========================
+
+The system can be easily extended through the use of your own libraries,
+helpers, or through class extensions or system hooks.
+
+CodeIgniter Does Not Require a Template Engine
+==============================================
+
+Although CodeIgniter *does* come with a simple template parser that can
+be optionally used, it does not force you to use one. Template engines
+simply can not match the performance of native PHP, and the syntax that
+must be learned to use a template engine is usually only marginally
+easier than learning the basics of PHP. Consider this block of PHP code::
+
+	<ul>
+	<?php foreach ($addressbook as $name):?>
+		<li><?=$name?></li>
+	<?php endforeach; ?>
+	</ul>
+
+Contrast this with the pseudo-code used by a template engine::
+
+	<ul>
+	{foreach from=$addressbook item="name"}
+		<li>{$name}</li>
+	{/foreach}
+	</ul>
+
+Yes, the template engine example is a bit cleaner, but it comes at the
+price of performance, as the pseudo-code must be converted back into PHP
+to run. Since one of our goals is *maximum performance*, we opted to not
+require the use of a template engine.
+
+CodeIgniter is Thoroughly Documented
+====================================
+
+Programmers love to code and hate to write documentation. We're no
+different, of course, but since documentation is **as important** as the
+code itself, we are committed to doing it. Our source code is extremely
+clean and well commented as well.
+
+CodeIgniter has a Friendly Community of Users
+=============================================
+
+Our growing community of users can be seen actively participating in our
+`Community Forums <http://codeigniter.com/forums/>`_.
diff --git a/user_guide_src/source/overview/cheatsheets.rst b/user_guide_src/source/overview/cheatsheets.rst
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+#######################
+CodeIgniter Cheatsheets
+#######################
+
+Library Reference
+=================
+
+`|CodeIgniter Library
+Reference| <../images/codeigniter_1.7.1_library_reference.pdf>`_
+Helpers Reference
+=================
+
+`|image1| <../images/codeigniter_1.7.1_helper_reference.pdf>`_
+
+.. |CodeIgniter Library Reference| image:: ../images/codeigniter_1.7.1_library_reference.png
+.. |image1| image:: ../images/codeigniter_1.7.1_helper_reference.png
diff --git a/user_guide_src/source/overview/features.rst b/user_guide_src/source/overview/features.rst
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+####################
+CodeIgniter Features
+####################
+
+Features in and of themselves are a very poor way to judge an
+application since they tell you nothing about the user experience, or
+how intuitively or intelligently it is designed. Features don't reveal
+anything about the quality of the code, or the performance, or the
+attention to detail, or security practices. The only way to really judge
+an app is to try it and get to know the code.
+`Installing <../installation/>`_ CodeIgniter is child's play so we
+encourage you to do just that. In the mean time here's a list of
+CodeIgniter's main features.
+
+-  Model-View-Controller Based System
+-  Extremely Light Weight
+-  Full Featured database classes with support for several platforms.
+-  Query Builder Database Support
+-  Form and Data Validation
+-  Security and XSS Filtering
+-  Session Management
+-  Email Sending Class. Supports Attachments, HTML/Text email, multiple
+   protocols (sendmail, SMTP, and Mail) and more.
+-  Image Manipulation Library (cropping, resizing, rotating, etc.).
+   Supports GD, ImageMagick, and NetPBM
+-  File Uploading Class
+-  FTP Class
+-  Localization
+-  Pagination
+-  Data Encryption
+-  Benchmarking
+-  Full Page Caching
+-  Error Logging
+-  Application Profiling
+-  Calendaring Class
+-  User Agent Class
+-  Zip Encoding Class
+-  Template Engine Class
+-  Trackback Class
+-  XML-RPC Library
+-  Unit Testing Class
+-  Search-engine Friendly URLs
+-  Flexible URI Routing
+-  Support for Hooks and Class Extensions
+-  Large library of "helper" functions
+
diff --git a/user_guide_src/source/overview/getting_started.rst b/user_guide_src/source/overview/getting_started.rst
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+################################
+Getting Started With CodeIgniter
+################################
+
+Any software application requires some effort to learn. We've done our
+best to minimize the learning curve while making the process as
+enjoyable as possible.
+
+The first step is to :doc:`install <../installation/index>`
+CodeIgniter, then read all the topics in the **Introduction** section of
+the Table of Contents.
+
+Next, read each of the **General Topics** pages in order. Each topic
+builds on the previous one, and includes code examples that you are
+encouraged to try.
+
+Once you understand the basics you'll be ready to explore the **Class
+Reference** and **Helper Reference** pages to learn to utilize the
+native libraries and helper files.
+
+Feel free to take advantage of our `Community
+Forums <http://codeigniter.com/forums/>`_ if you have questions or
+problems, and our `Wiki <http://codeigniter.com/wiki/>`_ to see code
+examples posted by other users.
diff --git a/user_guide_src/source/overview/goals.rst b/user_guide_src/source/overview/goals.rst
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+##############################
+Design and Architectural Goals
+##############################
+
+Our goal for CodeIgniter is maximum performance, capability, and
+flexibility in the smallest, lightest possible package.
+
+To meet this goal we are committed to benchmarking, re-factoring, and
+simplifying at every step of the development process, rejecting anything
+that doesn't further the stated objective.
+
+From a technical and architectural standpoint, CodeIgniter was created
+with the following objectives:
+
+-  **Dynamic Instantiation.** In CodeIgniter, components are loaded and
+   routines executed only when requested, rather than globally. No
+   assumptions are made by the system regarding what may be needed
+   beyond the minimal core resources, so the system is very light-weight
+   by default. The events, as triggered by the HTTP request, and the
+   controllers and views you design will determine what is invoked.
+-  **Loose Coupling.** Coupling is the degree to which components of a
+   system rely on each other. The less components depend on each other
+   the more reusable and flexible the system becomes. Our goal was a
+   very loosely coupled system.
+-  **Component Singularity.** Singularity is the degree to which
+   components have a narrowly focused purpose. In CodeIgniter, each
+   class and its functions are highly autonomous in order to allow
+   maximum usefulness.
+
+CodeIgniter is a dynamically instantiated, loosely coupled system with
+high component singularity. It strives for simplicity, flexibility, and
+high performance in a small footprint package.
diff --git a/user_guide_src/source/overview/index.rst b/user_guide_src/source/overview/index.rst
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+####################
+CodeIgniter Overview
+####################
+
+The following pages describe the broad concepts behind CodeIgniter:
+
+.. toctree::
+	:titlesonly:
+	
+	Getting Started <getting_started>
+	CodeIgniter at a Glance <at_a_glance>
+	CodeIgniter Cheatsheets <cheatsheets>
+	Supported Features <features>
+	Application Flow Chart <appflow>
+	Model-View-Controller <mvc>
+	Architectural Goals <goals>
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diff --git a/user_guide_src/source/overview/mvc.rst b/user_guide_src/source/overview/mvc.rst
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+#####################
+Model-View-Controller
+#####################
+
+CodeIgniter is based on the Model-View-Controller development pattern.
+MVC is a software approach that separates application logic from
+presentation. In practice, it permits your web pages to contain minimal
+scripting since the presentation is separate from the PHP scripting.
+
+-  The **Model** represents your data structures. Typically your model
+   classes will contain functions that help you retrieve, insert, and
+   update information in your database.
+-  The **View** is the information that is being presented to a user. A
+   View will normally be a web page, but in CodeIgniter, a view can also
+   be a page fragment like a header or footer. It can also be an RSS
+   page, or any other type of "page".
+-  The **Controller** serves as an *intermediary* between the Model, the
+   View, and any other resources needed to process the HTTP request and
+   generate a web page.
+
+CodeIgniter has a fairly loose approach to MVC since Models are not
+required. If you don't need the added separation, or find that
+maintaining models requires more complexity than you want, you can
+ignore them and build your application minimally using Controllers and
+Views. CodeIgniter also enables you to incorporate your own existing
+scripts, or even develop core libraries for the system, enabling you to
+work in a way that makes the most sense to you.