Added finalize method, added declare method, new member access handler, bug fixes.

Added __finalize method which is called when a class instance is about to be garbage collected. Works in Lua 5.1 and Lua 5.2!
Added __declare method which is called once a class has been declared. Useful for initializing statics.
Rewrote the entire system that handles member access. It now no longer uses the debug library and can detect calls coming from outside the class hierarchy.
Fixed bug when calling parent functions; it now passes the child object, instead of the parent object, to the function.
Fixed realpath bug: now gets rid of './'.
Fixed missing realpath in class setup.
Fixed bug where double class setup detection didn't work properly.