Merged some of the changes from ioq3 rend2.

* OpenGL2: Add r_ignoreDstAlpha.
* Make GL2 MDR code use R_VboPackNormal for normal
* Fix GL2 deluxemap 0,0,0 to 127,127,127
* Don't create images/framebuffers that won't be used
* don't call va each frame in GLSL_VertexAttribPointers
* Fix OpenGL2 non-HDR map surface over brighting