XF handles all low-level including initialization, database connection and basic abstraction layers
any 'action' inherit XFAction must define at least some common methods/vars...
XFAuth takes care of user authentication
XFCache provides an abstraction for caching organized in pools
XFCrypt_Blowfish is a cryptographic instance without depending on php mcrypt
XFDebug handles all debugging purposes and requires XF::DEBUG to be 'true'
well, XFE is my little own interpretation of a dump after catching an exception.
XFImage abstracts php image function to draw bitmap and vector based
XFLog provides a general-purpose logging facility
XFMail is currently a simple abstraction for mail()
XFParser takes care of text processing, tag management and some more
basic elements to inherit by XFTask for scheduled tasks either...
XFUI class handles user interface methods
do neccessary xml payload encoding