lispy.el (lispy-delete): less whitespace-hungry

* lispy.el (lispy-delete): When looking at `lispy-right', go outside
  list instead of instantly deleting it (can delete in the next one
  anyway). This is the same behavior as with strings now.
  (lispy--delete): Delete less whitespace.

* lispy-test.el (lispy-delete): Update tests.

Fixes #29.