New feature: collidable moving parts

[robn]

I've just merged support for collidable moving parts. This means two things: you can specify multiple collision meshes per model, and those meshes will animate correctly with the model node they're attached to. The obvious immediate application is for landing gear and station doors, but no doubt you'll all think of something.

See PR #2493 for details on how to use it and a sample model to experiment with.

This only has minimal testing so please report any weirdness. I'm particularly interested in how it might affect performance with complex meshes and/or lots of models.

[NeuralKernel]

Moving Parts, eh?

Does collision with parts on OTHER ships work? :D

[Nyankosensei]

2 problem for use them

1) Collidable moving part are not showed in modelviewer

2) When i export from blender i need to expot object from the last frame of animation for make them work