OmniLight3D:
* Fixed lack of precision in cube map mode by scaling the projection's
znear.
* Fixed aliasing issues by making the paraboloids use two square regions instead of two half
squares.
* Fixed shadowmap atlas bleeding by adding padding.
* Fixed sihadow blur's inconsistent radius and unclamped sampling.
SpotLight3D:
* Fixed lack of precision by scaling the projection's znear.
* Fixed normal biasing.
Both:
* Tweaked biasing to make sure it works out of the box in most situations.
