visually distinguished totally metal-depleted rubble
added note to restore conservation of mass later
made conveyor desc more correct from user perspective
Started brewing up some gas physics code.
Hacked at the gas physics some more.
bit of incomplete prototyping with Eli
make gl_rendering's gl_widget optional (no text then)

This might be useful for testing something
fix color ostreaming for near-0-value components.
Make grand_structure_visualizer be. (Hackily and initially).

It now displays!
sort GL triangles in the right order for alpha channel.

(Not actually visually tested because the ordering doesn't
make a difference in the current display.  And it can't
be perfect, but it can be decent.)
Merge branch 'master' of https://github.com/idupree/Lasercake
crudely, let you watch tetrahedrons move
Made things a reasonable scale (m, not nm, in size).
Switched to nonconvex/holey polyhedral regions
adjusted some locations and sizes
Switched to a plane-centric model.

We no longer define vertices except as a function of
   the locations of their incident planes.
Fixed bug where velocity didn't update
fixed name of misleadingly-named function
implemented "when planes collide" function

(didn't test)
fixed using wrong type