Time: improvements to 'tztime'
Time: improvements to 'tztime'

- Import pytz on load, not every time the command is called
- Respect plugins.time.format
- Use irc.error(e, Raise=True) instead of return

ProgVal/Limnoria-test,ProgVal/Limnoria-test,Ban3/Limnoria,Ban3/Limnoria