Implement the oper override commands

This PR includes the following commands:
- SAJOIN
- SAPART
- SAMODE
- SANICK
- SATOPIC
- SAKICK

I was thinking about maybe making them a bit more user friendly by prepending the part reason, kick reason and topic with a colon, but that's kind of up to the client.
For some reason I did not notice that parameter was there. It's fixed now.