GDC 2006 2D Physics Demo for D

[clayasaurus]

After quite a conversion process, I've successfully converted the c++ 
GDC 2006 2D Physics demo to D.

Original:
http://www.gphysics.com/archives/18

D Version: 
http://www.dsource.org/projects/arcgames/browser/trunk/physics/demo.zip?format=raw

Use keys 1-9 to switch through demo, and space bar to launch the 'bomb'.

It also comes with a public domain red black tree implementation that 
seems to work. The author of 
http://eternallyconfuzzled.com/tuts/redblack.html told me he is going to 
add a license page that says all the code on his pages are in public 
domain.

Special thanks to Christian Kamm for helping me track done a bug.

~ Clay