Doing normalization of normals / binormals / tangents in fragment shader instead of vertex shader. This seems to help with artefacts appearing in certain models with OpenGL rendering backend.

Also added modulating environment reflection by specular map.

Implemented again @ekitson's improvement to GeometyUrils.center. Increased light intensity in loader_json_blender example.

Turns out it may be useful after all, seems some GPUs may have troubles dealing with texture coordinates outside of <0,1> (need to be tested if normalization helps there).

Added option to ColladaLoader to recenter all Geometry so that they are centered around the local origin of their containing Mesh.

As per discussion here:

https://github.com/alteredq/three.js/commit/457be13975345dcd53f5a07f38ac09b5bada5f0b

Is not used so much anymore so we can have it with a less obfuscating syntax.

This is optional, for now by default it's off, like it was before. It's up to application to update geometry bounding sphere if vertex positions change (like for meshes).

Should fix #779...

Animation / skinning / path controller are now broken :/