HDR EnvMap example with high quality, flexible PMREM Generator.

Output encoding

Remove example materials_variations_standard2

float and half HDR CUbe Maps load and are properly generated.  Something wrong when using RGBE encoding.

# Conflicts:
#	src/renderers/shaders/ShaderLib.js
#	src/renderers/webgl/WebGLPrograms.js

move fog_fragment after encoding, the reason is the background/fog colors are not encoded and we need to get perfect blends.

because now its basically the same as the other without metalness.

'reflectivity' is not a property of mesh standard material

Made OBJ converter for Python3 working by changing xrange to range.

Documentation for BufferGeometry entities

clean up of texture.encoding support of WebGLRenderTarget