multiple SGraphicsChai

[brian soe]

SDatabase contains a CMappedList of SGraphicsChai. And SGraphicsChai contains:

 chai3d::cWorld* chai_world_;

 sutil::CMappedList<std::string,  sutil::CMappedTree<std::string, SGraphicsChaiRigidBody> > robots_rendered_;

 sutil::CMappedList<std::string, SGraphicsChaiMesh> meshes_rendered_;

 sutil::CMappedList<std::string, SGraphicsChaiMuscleSet> muscles_rendered_;

This suggests multiple independent simulated worlds with robots. What if instead SDatabase contains one SGraphicsChai. And SGraphicsChai contains:

 sutil::CMappedList<std::string, chai3d::cCamera*> muscles_rendered_;

Which suggests one simulated world with robots, with multiple rendered instances of that world. In SDatabase, there can be a CMappedList of the glut variables for each rendered window.

[Samir Menon]

I think it's fine to support multiple graphics worlds. They might have different meshes for the same robots etc., which could simplify debugging collision detection etc.