lispy.el (lispy--insert-or-call): save-match-data

* lispy.el (lispy-down): Wrap in save-match-data.
  (lispy-up): Wrap in save-match-data.
lispy.el (lispy-eval-other-window): works for all let-bound vars
lispy.el: re-bind "C-4"

It still does the same thing as "x", but now it's just a standard Emacs
map, so things like "C-4 ?" are given for free.