Clean up the viewer

For some reason, this improves performance in the viewer. I just removed
a lot of shit, don't ask me why it did that.
Remove onDown
Remove some more cruft
Remove hasShaderHardware

It's just flat out wrong, first of all, and nothing we support nowadays
doesn't have shaders.
Remove wireframe mode and some other cruft
Remove more cruft
Clean up drawSceneGraph
More cleanups and rearrangements
A few more cleanups
Clean up shader generation code
Remove setStartupText
Simplify alpha tests
Clean shader generation some more
Clean up mods generation
Use constant booleans for alpha comparisons
Clean up vertex shader generation