* Ideas [3/5]
** DONE rectangular-region-mode
   Switch to a specialized multiple-cursors mode, anchoring it to the current
   cursor position. Moving around increases/decreases the size/number of cursors,
   to simulate vertical editing in textmate.
** DONE Cycle through cursors
   To scroll the buffer and watch all your cursors - make a keybinding for
   promoting the next/previous fake cursor.
** TODO Create replacements for common non-working commands
   Possible to do C-s ...
   Any way to make M-z just prompt for letter once?
** TODO mark-multiple-mode
   mark-multiple has some advantages
    -> simpler visuals, no extra cursors (matter of taste?)
    -> moving out of the marked area quits the mode
** DONE unknown command: Do for (a)ll, (o)nce or (i)gnore -> (did that work ok? (k)eep doing that or (d)on't)
   unknown-command ran once - what now? (o)nce is enough, repeat for (a)ll, (u)ndo - that did NOT work.
   unknown-command ran for all - did that work as expected? (y)es, (n)o
   what to do about unknown-command in the future? Run it (o)nce, or (s)top it from being run.
* BUGS: [4/4]
** DONE with multiple regions active, C-d deletes only a char in the fake ones
** DONE 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
** DONE clean up overlays when reverting buffer
** DONE rectangular-region-mode fails when lines of the buffer have been hidden (ref collapse in org-mode)
* TODO: [5/6]
** 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 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.
** DONE add tests