first pass at GeometryFilters.computeNormals
added new test for computeNormal
computeNormals takes mesh as a parameter
added documentation
Merge branch 'batching' into computeNormals

Conflicts:
	CHANGES.md
computeNormals uses vertex data in correct way
updated tests to reflect this
minor changes to documentation and variables
Merge branch 'batching' into computeNormals

Conflicts:
	CHANGES.md
Merge pull request #774 from hpinkos/computeNormals

Compute normals