Introduce computeOffsets() and reorderBuffers() to BufferGeometry.
computeOffsets - Algorithm specially tailored to chunk large models into multiple draw offsets of 65535 addressable vertices.
reorderBuffers - Method to remap attributes based on a new index buffer.
CTMLoader now uses BufferGeometry's computeOffsets() to chunk large models into usable draw calls.

Conflicts:
	examples/js/loaders/ctm/CTMLoader.js