Use uint8_t in more places to indicate binary data.

Also annotate a bug in mush_crypt_sha0 that causes password verification
to be more generous than it should. While this bug /shouldn't/ appear
too much in practice since it still relies on generating SHA-0
collisions, it'd be nice to fix. We should also salt our hashes...

git-svn-id: https://pennmush.googlecode.com/svn/trunk@1794 ba372814-4f39-11de-9ad6-1127a62b9fcd