Fixed LOD pathing issue so that LODs work again.

Added Sandstone mullions so if you have the Sandstone Blocks mod, you can make decorative stonework that matches.

Minor research bugfix

Updated for 0.6, added glass-break sound effect

Major optimization pass.

Reduced total number of textures and "transparent materials" by a large amount.

Cleaned up the leaded-frame meshes to use many fewer polygons, removed redundant and "degenerate" points. Should be a lot nicer to processors now.

Updated in-game descriptions of Rough Sand, Basic Glass, and Stained Glass to show better how and where to craft them.

Fixed the strange dark shading on the distant views of the stone mullion.