Better time limit handling

- Don't assume slow mode on default (currently, you start with the 20 second timer when there is a 5 sec limit and ther eis no slow mode message)
- Adjust time limits when last message could not be sent (when time limits are wrong or the 30 second repeated message timer is actually a 35 second timer)
- Added handling for when user is banned (Happens more often than you think)
- Alter some admin messages to be more meaningful with the timer, remove slow mode messages if slow mode time limit wasn't changed.