Pipes are now colored with color var, cleanup.

Exposed pipes now have proper icons for T-ray scanner
Removed unused icons
Fixed bunch of things

* Manifolds now uses an overlay system, cleaner than ever. Manifolds now
display properly using T-ray scanner, showing broken ends, etc
* Manifolds can be colored with the color var
* Fixed pipe shading, now consistent
* Removed the pesky "dirt" thats on the end of every pipe, lines of
pipes now more visually pleasing