* TODO: [4/9]
** DONE (set-marker MARKER nil) for performance
** DONE C-g deactivates regions first, before disabling multiple-cursors
** DONE more state to save per cursor: er/history
** DONE refactor: an object with all the current state, used for both overlays and current
** TODO add tests
** TODO collapse cursors at same point
** TODO unknown command: (t)ry all, (i)gnore -> (did that work ok? (k)eep doing that or (d)on't)
** TODO separate mark-multiple and multiple-cursors
   mark-multiple goes back to being the util? or just dies?
   given the problem with extract-var and undo, may just kill mark-multiple.
   problem with that is: C-g when doing rename-tag shouldn't go to multiple-cursors.

** TODO there's something going wrong with last-command/this-command?
   expand-region works nicely, even collapse when we save er/history, but last collapse puts all cursors in same spot