Add rpl_away support

- Add awayMsg to user object
- Display awayMsg in userlist
Add AwayChecker service

- Scan away status every 30 seconds
- Handle G and H flags in rpl_whoreply
Add truncate filter

- Truncate away message to 7 chars
Fix errors regarding text being null
Add AFK and BACK commands

- Add 305 and 306 numeric support
Update own user's away status instantly
Truncate own user's away message
Fix truncate filter to always truncate long strings
Merge pull request #33 from coldstorm/away-support

Add away support