Dimension Teleporter

1.3.2: mitigation: use getPlayerExact to prevent potential mistakes when targeting a player (thanks to Aikar for pointing this possibility out).

1.3.1: fix: apply colors to /dt
Forgot to apply the coloring to the /dt command as well.

1.3: Added /dtspawn - teleports you to the current world's spawn location.

1.2: Displays list of worlds
- Displays a list of worlds when no arguments are used, or when an invalid world has been specified.
- Added some colors to messages.

1.1: Permissions are now all lowercase
I'm not sure what the standard convention is for permissions, but I remember putting all my permissions in lowercase. Maybe it doesn't matter :S