Ahtable load save

Adds the ability to load and save an ahtable object in architecture-agnostic way (uses 64-bit values where there is ambiguity).

I sent an earlier version of this pull request to luikore, but since we're merging code bases, I thought it made the most sense to start work on the main repository.
It'd be better to just use `uint64_t` instead of `unsigned long long` since the former is guaranteed to be 8 bytes.