Refactored CTMLoader to use BufferGeometry.computeVertexNormals (for when CTM file doesn't have normals).

Still some more cleanup should be possible, e.g. it would be nice to get rid of GL context dependency.

Also extended CTMLoader example to test geometry sharing plus few other tweaks.

Fixes issue raised in comment to #2166

Added dynamic updating of BufferGeometry. Added BufferGeometry.applyMatrix. Added Matrix4.multiplyVector3Array.

CTMLoader now keeps references to typed arrays used to initialize GL buffers. These are later on deleted in WebGLRenderer (by default, if BufferGeometry.dynamic flag is not set).

Fixes #2166

(this commit should go to `unflipped` branch, it assumes straightforward UVs)

Don't try this at home kids. Finally had to do it like this, alternative was just getting slowly insane (I spent lot of time on futile attempts to make it in the "right" way, it doesn't even show any texture with UNPACK_FLIP_Y_WEBGL toggled on).

For some reason point sprites in "natural" orientation are upside down :S

I think normal map scale needs to be now positive, though not sure, it just looks closer to how it was before with positive scale, also mole on the right cheek is elevated instead of sunk.

Previous one had messed up mouth.

Still our normal mapped models now look different than before flipping. Not sure if this is desired or some problem (tangents do depend on UVs).

This fixes postprocessing example.

Tomorrow Geometries and CanvasRenderer.

Please note that render target must be power-of-2 sized for this trick to work. Other option would be to change directly UVs in the geometry (though that would make it harder to swap image vs render target as texture or to share geometry between objects using materials with images vs render targets).

Fixes #2164

Please note that render target must be power-of-2 sized for this trick to work. Other option would be to change directly UVs in the geometry (though that would make it harder to swap image vs render target as texture or to share geometry between objects using materials with images vs render targets).

Fixes #2164

See discussion in #ab6e9f75