Tracks Rhapsody buff from priest class tree.
Includes a swipe timer to indicate when the next stack will be added to the buff. The buff stops at 20 stacks. The timer resets whenever you cast Holy Nova.
There's a weird bug (in-game) where the buff won't stack until you cast Holy Nova at least once after a talent change. Whenever this happens, the aura has full color+glow without any stacks. I don't intend on handling this edge-case.