add visual return feedback for no-cursor and clamp reaches

[thartbm]

In some case, there will not be a stencil to guide people's return movements, but we can give them impoverished feedback that does not show them the exact position of the cursor/hand. Namely a ring that just indicates the distance from home, or an arrow-head at the home position that indicates the home position in a set number of angular bins, with one of them centered on the target (in our experience 8 bins of 45 degrees makes sense).