Implement the X:Line commands

This PR implements the following commands:
- KLINE
- GLINE
- ZLINE
- ELINE
- QLINE

With the exception of server to server support (which I'll get on once this is reviewed) they are fully functional. I did run into a slight problem with the ZLINE commands, where it disconnects a Z:Lined user with a broken pipe rather than the actual ban reason. I'm not quite sure how to work around this issue.