Reviving BulletD -- again

[BLM768]

After a significant hiatus, I've decided that I need to get 
BulletD up and running again. I think that the main reason it 
died was just that I felt so overwhelmed with the sheer magnitude 
of the project, and I've realized that there's no way I can 
finish it myself in a reasonable amount of time, so I'm issuing 
an invitation to anyone who's interested in helping to get it to 
a functional state.

Here's the project's current status:

I've gotten about 7,000 lines of code ported (which, by my 
estimates, is under 10% of the codebase), but it needs to be 
revised to be up-to-date with the latest version of Bullet, and 
my earlier misguided attempts to make the memory allocators more 
"D-friendly" need to be reverted to the original form used in 
Bullet. I'm also probably missing some parts of the modules I've 
ported, so I'll need to get those fleshed out.

If anyone feels like participating, feel free to port a module or 
two and submit a pull request at github.com/blm768/bulletD. The 
current focus is getting the already-ported modules revised (and 
rewritten where necessary), especially in the linearMath 
subdirectory because so many modules depend on that code.