Refactor MCF parsing
Support reading $7$ prefixed MCF hashes
Require correct hash lengths
Increment version number for git master
Merge branch 'mcf-7'

Modular Crypt Format $7$ prefix read (scrypt_mcf_check) support according to:
https://gitorious.org/scrypt/scrypt-unix-crypt/source/unix-scrypt.txt

See issue #1