Watch out, he's got a whitespace change! ^^
Also check the permissions for senders that are not instances of Player.
Change method name from sendMessage() to performAction().
Added the classes to assign permissions to a user on Teamspeak.
This adds a PermissionsHelper, which looks up permissions from a file -
permissions.yml - and stores the data in a ServerGroup object.
Those objects can be retrieved by their server group ID.