lispy.el (lispy--normalize): fix

* lispy-test.el (lispy--normalize): Add.
lispy.el (lispy--eval): add support for Scheme

* lispy.el (lispy--eval-scheme): New function.
lispy.el: re-arrange code
lispy.el (lispy-tab): add and bind to "i"
lispy.el (lispy-shifttab): add and bind to "I"