separating out memory checks from INVARIANTS

[Kip Macy]

I find that the serialization of memory allocation frequently hides
race conditions. I would like to, at the very least, add an option to
disable the memory checks if not make the memory checks a completely
separate option. My knee jerk reaction to avoiding bikesheds is to
simply add it to my own tree and forget about it. However, this has
come up often enough that I feel that it warrants consideration.


Thoughts?

 -Kip