Added vertex cache optimization
Added releaseGeometries option
Added transformToWorldCoordinates option
Added depth-only for primitives that are not pickable
Added support for OES_element_index_uint
Merge branch 'batching' into boxGeometry

Conflicts:
	Apps/CesiumViewer/CesiumViewer.js
Modify tangents and binormals to match the texture coordinate directions.
Add czm_tangentToEyeSpaceMatrix built-in GLSL function.
Add tests.
Add doc.
Update CHANGES.md.