Use `paredit-preserving-column' in `paredit-reindent-defun'.
Make sure M-? leaves space appropriately when there was none.
Bind M-[ to paredit-wrap-square.
Flesh out paredit-wrap-... tests a little.
Make slurping `(|) foo' yield `(|foo)', not `(| foo)'.

Likewise for backward slurping and slurping into strings.

Add some tests.