TeamKind cleanup, warning fixes, closes gh-631

TeamKind has been changed to store colors in a DyeColor object instead
of using a byte value store. This improves readability and makes the
code future-proof.

All listeners are now unregistered when the plugin gets unloaded. This
removes the need for listeners to check if War is loaded and prevents
duplicate registration. I would prefer if the ability to unload and load
the War plugin was completely removed, however, as there are plugins out
there such as PlugMan that are dedicated to cleanly reloading plugins.

The main purpose of this was to clean up all issues and problems
reported by the eclipse java IDE. 0 warnings are shown by the IDE now.