[Mesa-dev] Mesa source re-org

[Brian Paul]

The new shader-file-reorg branch moves a bunch of Mesa source files to
re-organize things a bit.

1. Move all GL entrypoint functions and files into src/mesa/main/
This includes the ARB vp/vp, NV vp/fp, ATI fragshader and GLSL bits
that were in src/mesa/shader/

2. Move src/mesa/shader/slang/ to src/mesa/slang/ to reduce the tree depth

3. Rename src/mesa/shader/ to src/mesa/program/ since all the
remaining files are concerned with GPU programs.

4. Misc code refactoring.  In particular, I got rid of most of the
GLSL-related ctx->Driver hook functions.  None of the drivers used
them.

Some of the commits were huge so they probably won't show up on this list.

I'll be on vacation next week so I probably won't merge this to master
for a while.

-Brian