Add `find-function' keybinding

Learned about this function from
http://article.gmane.org/gmane.emacs.orgmode/82237.
Make `create-python-test-file` find file if exists

Instead of raising an error if the file exist, just open file in other
buffer.
Swap python test and compile keybindings

I keep using the wrong one, so I must think it makes more sense this
way.
Restore window configuration after shell command