Improve repeating "cw" etc.  (c3l<text> doesn't quite work yet).
* The movement function is passed in to pending_action, so that it can be
re-used.
Fix a lockup when using J on the last line.
Support Ctrl-^ to switch back to the previous buffer.
Some work towards trying to get jumping to errors from make output to work
(still not working).
When :find finds multiple matches, put them in a list rather than just an
error message.