Generator wrapper missing send and throw functions.

[Maxwell175]

I noticed that interrogate-generated generator wrappers are missing "send" and "throw" functions, however Panda3D's pythonTask depends on it: https://github.com/panda3d/panda3d/blob/master/panda/src/event/pythonTask.cxx#L640

It would be great to have these added in order to be compatible with Python generators.

[rdb]

Implemented in 4cf93da, I also made PythonTask more robust in panda3d/panda3d@00b5357.