Increase dps/tank raid frame height.
Improve nameplates and fix several issues.

Improves performance by removing unnecessary updates, allows visible
nameplates to take on a grey colour when a mob is tagged, and attempts
to fix issues with cast bar being wrongly sized and positioned on show.
Add highlighting for most valuable quest reward.

This highlights the quest reward with the highest vendor value. Still
trying to work out a few issues on this one.