WowAce

Oakshlaran:
    - Add display indication of disabled (dead/offline)
    Previously, the only way to tell that an interrupter was dead (using the
    addon) was if there were in a rotation, as then the rotation would skip
    them, but there was no explicit indication that their interrupt was not
    available for use.
    
    To rectify this, the frames now fade out and the test changes to
    OFFLINE/DEAD in gray. To facilitate this the colouring system was
    refactored slightly, with a new 'disabled' colour added to settings.
    
    Known issues:
    
      -    The call to update the colouring of frames in a rotation is made
           far more often than necessary, as RotationHighlight is called for
           each frame, but this function in turns colours all the frames in
           the rotation.
    - Rename addon to 'Oak Interrupts Display'