[Bf-vfx] OCIO branch

[Antony Riakiotakis]

There is, AFAIK a way to request an sRGB framebuffer from openGL. So
we could, in theory do everything in linear space and let the GPU
display stuff in sRGB. There will always be need for conversions
though because when we load images they will need to be converted to
linear and this entails quite some problems with precision. I'm not
certain a float format is indeed the way to go, they are quite
expensive bandwidth wise.