title: zsh: stop backward-kill-word on directory delimiter
body: <p>In <a href="http://www.zsh.org/" rel="noreferrer">zsh</a>, how can I set up the line editor such that <code>backward-kill-word</code> stops on a directory separator?  Currently in my bash setup, if I type</p>
  <pre><code>cd ~/devel/sandbox
  </code></pre>
  <p>and then hit <code>C-w</code> point will be right after <code>devel/</code>.  In my zsh setup, point would be after <code>cd </code>.  I'd like to set up zsh so it behaves similarly to bash.</p>