External user supplied dictionary for uncracked handshakes

[RealEnder]

This will work like this:

1. First time the client sends user dictionary request with empty hash. The server returns first uncracked handshake
2. Next the client sends last attached handshake hash
3. The server returns next uncracked handshake or empty if there is no new submitted handshake
4. The client sleeps 666 secs, then tries again.