Fix shimmering on NVIDIA cards.

texelFetch was sometimes getting the wrong pixel.
Remove out of date comments.
Sort textures by height in TextureAtlas.

We waste significantly less space when we do this.
Save memory client-side by decoding DXT1 to BGR24.
Better variable name, comment.
Rename TriangleStrip to TriangleFan.

That is what it is, after all.
Add StructureGeomNotes.