Add check for "final" attribute of functions
Before adding a function to the set to be overrided by the trampoline class, check for the "attribute" of "final". This requires the current master of CastXML:
https://github.com/CastXML/CastXML/commit/8bec09e1cd6407a2d03f48fb1e77e1a4dabcc928
The Python version of CastXML should be updated soon.