Smoother animations and Variance Shadow Maps

Shadows:
* Added a new depth-fs/vs.c shader to store variance information used by the variance shadow map
* Variance Shadows are faster than the current implementation and was able to increase the shadow map size

Animations:
* Added material loading to the threejs loader
* Added bone interpolation based on play time

Loading:
* Improved load time by adding the ability to not render the scene while loading.