Fixed a bug in the DiffusePTMaterial where too much light was being reflected.
Added a variable member to Ray for storing a random value between 0.0 and 1.0.  It is used for anything that needs a per-ray random value, e.g. simulated motion blur.
Changed test settings.
Added a subclass of Instance for interpolating an instance between a start and end matrix: MatrixInterpolationInstance.