TLS: Adding heartbeat functionality.
Oops fixing broken comment.
Clean up heartbeat implementation.

- Fix state table bugs.
- Enable heartbeat messages at any point during connection.
- Support heartbeat requests and responses.
- Rename heartbeatReady to heartbeatReceived; the original name
  was in line with other callback names, but for heartbeats this
  was a bit confusing -- "received" seemed better.
- No tests for this yet.
Copy forge.util.ByteBuffer if given to constructor.
Add docs for heartbeatReceived handler.
Add experimental heartbeat example.
Discard payload if length is too large.
Update manual tls test to include heartbeat; fix bugs.
Allow different payload length to be sent in request for heartbleed test.
Add quick (not robust) heartbleed detector.
Switch style to use more popular same-line bracket w/else and catch.
Update style in boilerplate.
Fix style.
Fix style for tests.
Update RSA signature docs w/signature algorithm details and PSS example.
Add note in examples for key gen worker estimation.
Use SHA-256 w/Fortuna; start 0.3.0.
More strictly follow Fortuna; reseed on every new request.
Use SHA-256 by default instead of SHA-1; expose createInstance.
Add example for creating new PRNG instance.