Merge pull request #89 from oerpub/58657378-boxes-and-spacing-2nd-attempt

58657378 boxes and spacing 2nd attempt
don't go up too far when previewing drag

just do the closest semantic container, not all ancestors
don't show .image-edit if any old ancestor is focused
put appropriate text in nested drag tooltips
Merge remote-tracking branch 'origin/nested-semantics-issues-57600192' into testing