Some caching improvements that should satisfy thread-safety.

Hi Mike,

I managed to take a peek at the caching implementations in your MeCache feature branch, and while I haven't had the chance to test any of this out yet, I expect that these changes will help guarantee thread-safety in the Glass caching layer.

I have to take off, but please feel free to look this over and let me know your thoughts.

If I'm able, I will try to get this build running on a development environment version of one of our projects in the near future.

Thanks,
Chris