Diff for Doc/Dev/SpecialFiles between 2 and 3

+ Special files

**##red|This information is valid for Horde 5 and later only. See ((Doc/Dev/SpecialFilesH3)) for Horde 3 or ((Doc/Dev/SpecialFilesH4)) for Horde 4.##**

* {{horde/lib/core.php}}: This file
 * sets some required PHP configuration settings
 * sets autoloading paths for Horde libraries
 * registers error handlers

There are several files with a special meaning that can be found in every Horde application:

* {{index.php}}: This script is loaded if a user enters an application. Usually this script doesn't have any functionality but simple loads the default view of the application, sometimes depending on the user's preferences.
* {{lib/Api.php}}: This files defines and implements all methods that an application is exposing through the ((Doc/Dev/RegistryH3|Registry))((Doc/Dev/Registry|Registry)) to the other Horde applications and the Horde RPC servers.
* {{lib/Application.php}}: This file defines information need to initialize the application and to interact with the Horde framework. It also defines the version number of the application.
* {{lib/Exception.php}}: This file defines the application-specific exception class.
* {{lib/Test.php}}: This file defines any application specific tests to run when using the Horde test script.
* {{lib/Ajax/Application.php}}: This file defines the AJAX actions provided by this module.
* {{themes/default/screen.css}}: This is a CSS file that defines all application specific style sheet rules.