Added support for start, pause, stop, and restart to ProgrammableCameraController.
Added tessellation to Cube.
Added tessellation to Sphere.
Fixed a texcoord bug in Triangle (they were using the normals of the vertex instead of texcoords)
Added a roughness parameter to DielectricPTMaterial (works but isn't mathematically pretty).
Started an implementation for Dipole SSS. (Not yet functional!)
Changed test settings and added a new test scene, TestScene8.