Update from 14.01.2018

[pervokpetr]

New update was sent:
- fix for Oculus FOV error
- changed environment lighting/skybox params
- added fog

Oculus FOV error
After notice from "aautobot" about wrong separation under Oculus, I check my code and found only one place that can cause problem - I used default fov for oculus instead of accured from device, so I hope now this problem will be solved

environment lighting/skybox
Now this components of environment has identical parameters: curve, scale, saturation - curve from now will not increase saturation and will work more like contrast, and saturation parameter will allow you adjust saturation of both components in depends from situation

fog
Opportunity to use fog in scenes, used height based fog algorithm

base_level - zero height - i.e. height where fog start
density - density of fog
height density fallof - speed of fallof density with growing height from base_level
sun_scattering - amount of light that will affect fog
sun_halo_amount - amount of visible sun glow behind fog
sun_halo_spread - size of sun halo
fog_affect_sun - amount of reducing sun light that will be received by surfaces