srcbuiltins module: Added gpGlobals class and added string_t converter. gpGlobals ref is also added to the Python builtins module, so it can be accessed anywhere without importing.
Python Entity support:
- Entities are now properly destroyed
- Added Think support
- Added Touch support
Added my_model_entity example from VDC, implemented in Python. Added a test command for destroying all my_model_entity instances, showing what happens to the handle and instance refs when destroyed (py_example_mymodelentity_removeall).