PythonQt Code

- added support for deriving CPP classes in Python and to override all public and protected virtual functions from PythonQt
- changed signal receiver code so that it can be reused for virtual method dispatch
- moved decorators completely into PythonQtClassInfo
- changed python to qt conversion so that it can work with an already allocated object (needed for return values of virtual functions
- added support for multiple inheritance and upcasting (e.g. a QWidget is automatically casted to a QPaintDevice when passed to QPainter.begin())
- removed default constructors of std decorators because they are now codegenerated
- regenerated bindings

- improved the code generator to suppot

reorganized SVN tree into branches, tags and trunk