Blender Git Loki

Eevee:Uuse compressed format for probes.

One 1024px� octahedral probe (according to the GPU mem stats):
- RGBA16F = 17Mb
- RGB_11_11_10 = 4Mb
For the time being I prefer to maximize the number of probe possible in the scene for users to test.
This is obviously a temporary solution and the final choice of cubemap format should be exposed to the user.