* [ADD] Abstract classes and interfaces for better code structure.
* [MOD] Actions handled as integers not strings and are consistent accross app modules.
* [MOD] Classes' names where modified. Namespaces where added for better handling.
* [ADD] Common exception class for the whole app.
* [ADD] New base file for app initialization.
* [MOD] Speed improvements.
* Improved session cache's config parameters to reduce config file queries
* Removed unused methods
* Changed some SP_Crypt class methods to static and factorized some functions
* Added some stuff to demo mode
* Added class CssMin for minimizing CSSs.
* Cached some config values in session to avoid config file readings.
* Improved URL handling.
* Minor bug fixes.
