PythonQt Code

- wrapped instances are now wrapped by class specific subtypes to facilitate future deriving from python
- object creation has changed by using the python type system (calling the type object with PyObject_Call)

code cleanup and rename of PythonQtWrapper to PythonQtInstanceWrapper and PythonQtMetaObjectWrapper to PythonQtClassWrapper, since these names match much better what these classes wrap, regarding that we are wrapping CPP objects as well