MiliUI Unit Frames

New
- Target border: draws a border around the health and power bars of the unit you are currently targeting. Enabled by default on boss frames only; turn it on per unit under Units > Frame > Target border, and set the color and thickness under General > Target border color / Target border thickness.
- Boss frames now respond to the mouse across the whole frame, including the portrait, name and cast bar, so hovering anywhere highlights the frame and clicking anywhere targets the boss.
- Multiple boss layout: Grow direction now offers Rightward and Leftward for side-by-side boss frames, with a new Horizontal gap slider for the space between frames (Units > Boss > Frame > Multiple boss layout).

Fixes
- Debuff type highlight and the hover and target borders no longer cover the inspect button or the health and power text.