Cubemapper Fixes (#1627)
Refactoring and fixes for Cubemapper, cleaned it up, makes it really WYSIWYG
Makes them work on Scene viewport
Updates any time they're dirty
Barriers should be set properly now
Parallax for ambient envmap lighting
Diffuse lighting from envmap should be working properly now
Cubemap feathering is tighter by default now, should fix some "leaks" now that skybox is also a global cubemap