robust support for multiple duplicate vertices in Face3 and Face4, add handling of vertex colors and vertex UVs.
Geometry.mergeVertices: remove unused variables, rename non-descript 'o' to 'indices'.
add webgl_geometry_normals.html - example that shows vertex normals and face normals of standard geometry types before and after Geometry.mergeVertices
Merge remote-tracking branch 'bhouston/geometry-mergeVertices-fix' into dev
Updated builds.