Update dependencies
Add simple benchmarking
Optimizations

- Use digest rather than hexdigest
- Use gmpy.mpz rather than Python big integer
- Use gmpy.hamdist rather than bin().count('1')
- Generate one random seed and guess sequentially, rather than guess
  randomly every loop
Merged luac optimizations
Merge branch 'master' of github.com:dghubble/xkcd-hashing