Graph editor gizmos and pie menus

Graph editor UI improvements

Add gizmos for:

-Translate

-Rotate (for handles)

-Scale

-Box scale (lets you scale by selecting points in a box and dragging a box corner or edge) (can have hot-key modifier for scaling to center) (this might be the same as scaling, actually)

Add a pie menu for hiding/ unhiding/ soloing/ un-soloing:

-x, y, z

-location, rotation, scale