=========================================

Changes to the ref_gl OpenGL renderer

=========================================

* Defaults to trilinear filtering (looks nicer :)
* 32bit colour specified in PFD (instead of 24bit)
* 24bit Z, 8bit stencil
* Loads targas instead of other image formats where available
* Entity shadows use stencil buffer
* Lowered shadows closer to the ground
* Dont rotate shadows on ungodly axis'