Inside view improvements (GLSL raytracing)

[unhyperbolic]

• Raytrace even when some tetrahedra are negatively oriented
• Accelerate through the bananas ("Margulis tubes")
• Recalculate shapes button (i.e., save original manifold and start surgery from a copy of original again)
• Mouse over to get info about tetrahedron/edge num/face num/word