Add bcprov dependency.
Initial generate ns code.
Merge branch 'develop' into key-generation

Conflicts:
	src/mvxcvi/crypto/pgp/key.clj
Initial key-generation code.
Add generate-keyrings function.
Factor out some key generation functions.
Split up generation functions more.
Hint that PGP tags are integers.
Extend public-key, key-id, and key-algorithm coercion to PGP keypairs.
Simplify key coercion methods.
More key generation factoring.
Remove some unused requires.
Rename util -> io and key -> util.
Start cleaning up README.
Update docstrings in signature ns.
Add hex-fingerprint and validate key-algorithm keywords.
Move io code into data and signature, since it wasn't shared.
Make signature hash-algorithm an optional parameter.
Improve README examples and text.
Make hex-id and hex-fingerprint resilient to nil inputs.