shadertool: Fix adjust_ui_depth
shadertool: Fix disable & make conditional on 3D being enabled
Montague's Mount: Shaders dumped from game
Montague's Mount: Adjust UI Depth and disable shadows

I haven't managed to adequately fix the shadows yet, but I have a request for
my WIP fix, so here's the quick n' dirty disable.
Montague's Mount: Add README.md