[MATLAB] fixed problem that objects were sometimes returned as SwigRef

- add package name to matlab_classname stored in clientdata
- still write some diagnostics when running matlab if NewPointerObj returns a SwigRef,
but the text of the warnings is now clearer
[MATLAB] fixed bug that caused class-hierarchies to be incorrect in random cases

in MATLAB::classHandler, we were Deleting an object (class_name) with GetAttr,
therefore deleting the attribute itself. This caused errors when processing derived classes, as
the sym:name object could be garbage (it was set to "destructor" in my case).
[MATLAB] fix issue with classes derived from multiple base classes

fix SWIG_Matlab_ConvertPtrAndOwn to call the appropriate conversion function
via SWIG_TypeCast. In the previous version, the conversion always assumed that
a simple reinterpret_cast would do the trick, but that is no longer true if you
have multiple base classes.