Make it easy to add/remove muscles from simulations

[k11niakio]

Right now we might want to remove muscles for debugging, but most of the muscle rendering is embedded in the graphics pipeline and so it's quite annoying to remove it.

The graphics pipeline should support an easy enable/disable for muscles...

[Samir Menon]

This is primarily a graphics issue. The new visualizer fixes this partially. Will add support to enable/disable muscles on the fly, which should do the trick.

[Samir Menon]

I'll consider this fixed for now. We can run multiple visualizers. With and without muscles. Both will simply read the same redis q values and so will just render bones vs bones+muscles.