Added more events, etc.

- Redid that ugly Socket passing into nice Connection and BncConnection
classes.
- Added the ConnectionAuthEvent.
- The BNC server now keeps track of channels and attempts to make the
IRC client join all of them. (currently not working, due to channel bug)
- Copypasta’d the colors.dart from irc.dart.
- The BNC server will now ping the IRC client to see if it’s still
alive.
- Use args over my custom arg system.