Salt passwords before hashing

[jbobo]

• Renamed "password" field in auth table to "hashed password".i
• Added "salt" field in auth table.
• Switched hashing function to hashlib.pbkdf2_hmac.
• Switched to hmac.compare_digest.compare_hash() to prevent timing attacks.
• Added salt generated by os.urandom(60).

[ Issue #224 ]

Signed-off-by: jbobo j.ned@bobonana.me

[mtn217]

Travis is currently failing due to linter and 30 tests.