Ambient Shadows

We had a contact shadows technique from Alyx that was modified to work also as general ambient occlusion for s&box, but had some problems in edge cases.

I wanted to solve that and try to make it better than any other technique, making it more of a shadowing technique rather than approximating distance around a radius, I always see other games using screen-space based techniques for AO, and the more I see how them just blurring the buffer is the wrong approach.

Our Ambient Occlusion technique was remade and now more closely approaches how ambient shadows are done in the real world, deriving luminance directionality into account, it's still as cheap as the previous technique and miles faster than HBAO.

Ambient shadows from a car will occlude its bottom accurately regardless of the angle, there's also the plus that it gives a similar behaviour as bent normals from baked AO, but dynamically.

More primitive types are also included, Capsule replaced the Spheroid shape that was used previously, Sphere and Cylinder shapes were also added, these also affect reflections.