No ability to control frame rate from python

[natevm]

Right now, the GPU can't be regulated, and as a result, display managers tend to lag on linux when rendering even simple scenes.

Rendering complex scenes might still might lag the display manager, since even at a low FPS, the GPU might become saturated with work. But on smaller scenes, the rendersystem could be slept more often (eg, throttle to 30fps instead of 140fps), which would reduce display manager lag.