Fix point/vector casting in helpers header (rotate(), :754). Changed default display on 3delight. Removed -lintlt on PRMan shader compiler default command, and added framebuffer to list of PRMan displays. Changed Ashikhmin-Shirley diffuse block's default values. Removed light categories from Kubelka-Munk block (no illuminance, meant for "sandwich models"). Updated bronze example scene, Spline_2 block was using "hermite" basis and missing a control point.
