[ODE] .NET bindings

[Jason Perkins]

I've just merged the in-progress .NET bindings into the trunk. As I
said, these are still in progress, there are a lot of functions
missing but I can start a drawstuff scene, drop boxes and capsules,
and see them bounce around. I am going to finish implementing the
BoxStack demo, and then I'll go back and fill in the remaining blanks.
Find it in ode/contribs/Ode.NET. I had to make some changes to the
(premake) build system to get drawstuff to build as a DLL, and I added
dBodyCopyPosition(), dBodyCopyRotation(), etc. to play nice with the
.NET P/Invoke API.

On a related note, I noticed that we still have contribs for dRay,
dCylinder, and GeomTransformGroup. Should we remove those?

Jason