Main things of interest:
* IAnimationStateMachine - state machine for animations; can load
from json.
* AnimationTESR - automatic TESR for animated models.
* AnimationModelBase - same for entities.
* ITimeValue - time-varying value, used to control animation
parameters from code.
* TESRs can now be batched - look at TESR.renderTileEntityFast +
TE.hasFastRenderer.
* RegionRenderCache is not accessible to TESRs and other client-side
logic - MinecraftForgeClient.getRegionRenderCache.