Digests 🚀

More improvements to the performance.
This time focus on Digests.
Everything is X times faster now.

Sample digest performance test times for
10_000 iterations improved from 0.8s -> 0.03s for SHA-1

improvement! profit!

Swift Three

0.6.0

• Remove bridge() workaround for Linux (not needed)
• make MD5() public
• Update README
• Convenience HMAC initializer for String input
• SHA-2 fix #319
• HashProtocol -> Digest and refactor
• MD5 conforms to Updatable protocol and may be calculated incrementally
• Cipher protocol accepts Collection input now
• Swift 3 compatibility
• Multiplatform, Single-scheme Xcode Project
• Swift Package Manager fully supported (build and tests)
• Improved Linux support
• Travis configuration added
• Public interface tests added
• enum Authenticator -> protocol Authenticator
• CRC -> Checksum
• String.encrypt() returns hex string instead of Array
• removed String.decrypt()
• enum Hash -> struct Hash
• Convenience initializer of Array of bytes with Hex string. Array(hex: "0xb1b1b2b2")
• Fix reusability of ChaCha20 instance
• Replace optional initializers with throwable initializers
• Allow to set initial counter explicitly (AES block modes). RandomAccessCryptor.seek()