UPDATE MOUSEOVER UNIT

Fired when the mouseover object needs to be updated.
 UPDATE_MOUSEOVER_UNIT
==Payload==
None
==Details==
* Fired when the target of the "mouseover" UnitId has changed and is a 3d model. (Does not fire when ("mouseover") becomes nil, or if you mouse over a unitframe.)
** This appears to have been changed at some point, it now fires when mousing over unit frames as well.