New memory allocator starting

I've got the first bits of our private memory allocator in. It's a bit 
wasteful (allocation regions are multiples of 16 bytes) but it passes all 
the tests. cvsup and abuse heavily, please.

As a side-effect, it close to doubles the speed of life.pbc when running in 
the interpreter. (But it's rather pathological in its memory usage, and I 
wouldn't count it as typical)

					Dan

--------------------------------------"it's like this"-------------------
Dan Sugalski                          even samurai
dan@sidhe.org                         have teddy bears and even
                                      teddy bears get drunk

• New memory allocator starting by Dan Sugalski