More robust 'insert measures'

1. I'd like to be able to insert measures either before or after the selected measure. Always inserting BEFORE runs into difficulty when a measure is preceded by a frame. One must then insert the measures, delete the frame, and put a new frame at the desired place. (Would be nice to be able to move frames as well, but that's another topic.)

2. After inserting a single measure using INS, either a) the inserted measure should be selected, so that I can hit INS again, or b) if I hit INS again immediately after inserting a measure, the system should not say "you must select a measure first" but assume I want it to go in the same place.