Fix planet that can look low quality

Fixed non uniform sampling direction when evaluating multiple scattering

Added details about MIE_PHASE_IMPORTANCE_SAMPLING 1 code path.

Fixed missing include

Fixed multi-scattering to work again in the path tracer (it broke after code clean up). Thanks anonymous AO!

Merge pull request #4 from tcantenot/submodules-fix

Merge pull request #3 from tcantenot/shadowmap-fix

Fix shader compilation for raymarching when shadow maps are enabled

Adds --init to git submodule update command for proper initialization of submodules

Adds ImGui and TinyEXR submodules

SkyAtmosphere project

Updated message

Initial commit