The problem this tries to address is - how to incorporate surface normals into diffuse term area light calculations. The original approach completely ignored surface normals, which resulted in both light shining on backfaces and lit surfaces not showing any shading. This made prettier empty box with very soft look but anything inside the box had completely flat diffuse term.

Not yet fully solved. I tried myriad variants, all methods I could come up with had some problems. This one for example breaks down when the light emitter area intersects object triangle :S.

Also fixed handling of vertex colors for emissive term and tried a bit closer match with shininess strength between area lights and other light types, though this is tricky, seems it would require some non-linear mapping.

Fixed inconsistent precision for lensflares and sprites shaders causing troubles on mobile (thanks to @phoboslab).

See #2769

expand Matrix3 with set, identity, copy, multiplyScalar, deteminant, clone;  Matrix3/4.getInverse will now optionally throw an exception; start Matrix3/4 unit tests

Official comment from VM guy is that it isn't needed.

Still waiting for an "official" recommendation from a VM guy though.

Also moved some more ui.js styles to the app's css.

I tried to replace the box.js with CubeGeometry but I guess material.side is still not implemented.

WebGLDeferredRenderer: made attenuation parameters properties of AreaLight instead of hardcoded constants.

Up vector can go outside of the shader. Attenuation can be computed only for lit pixels.

Also removed magic 1.5 constant in diffuse term.

Using original ArKano22's way:

http://www.gamedev.net/topic/552315-glsl-area-light-implementation/