This is a much better way to work with our commands dynamically. It
allows for localized description strings, aliases, etc.

With this addition, our "ugly alias" method in CommandPreProcessEvent is
no longer needed, nor is our alias map.

This also makes us more friendly with Essentials - if Essentials is
enabled, the /repair command will be changed to /mcrepair for
compatibility reasons.
Rework /addlevels to use the built-in Bukkit command stuff.
Having an option to disable commands from the config was a bad idea that
encouraged lazy admins. 

NOTE: If you were using these config options instead of relying on
permissions, you will need to reconfigure these commands to be disabled
via permissions.
Refactoring of general commands - the prior package structure made no
sense.

New package structure splits commands into those normally reserved for
admin use and commands normally available to all players.
Removed redundant permissions check for skill commands.