title: git: Automatically stash+pop on checkout
body: <p>If I do <code>git checkout my-super-branch</code> git tells me:</p>
  
  <pre><code>error: Your local changes to the following files would be overwritten by checkout:
      somedir/somefile.py
  Please, commit your changes or stash them before you can switch branches.
  Aborting
  </code></pre>
  
  <p>Is there a simple way to tell git to do stash+pop automatically?</p>