Framework update

In keeping with my promise to work on the cryptography code, I've fixed up key generation, added symmetric encryption/decryption, MAC generation and verification, and numerous other little bug fixes. There's also quite a few patched memory leaks, which I forgot to mention in the release notes.

Unfortunately, the whole thing probably still leaks like a sieve. I don't want to focus on the leaks directly until more features are implemented, so if you're having issues, you'd best spend a little time fixing it yourself. That's what this whole open source thing is about. :)