title: Webpack thinks there are two files whose names differs only in case only
body: <p>For no reason I start to see these messages appearing on the console where I use npm to start my test server:</p>
  
  <pre><code>WARNING in ./app/scripts/models/plan.js
  There is another module with an equal name when case is ignored.
  This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
  Rename module if multiple modules are expected or use equal casing if one module is expected.
  
  WARNING in ./app/scripts/models/Plan.js
  There is another module with an equal name when case is ignored.
  This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
  Rename module if multiple modules are expected or use equal casing if one module is expected.
  </code></pre>
  
  <p>However if I do a <code>ls</code>, there is only one such file in that directory and the name is in capital.</p>
  
  <pre><code>ls -l                                                                                                
  total 40
  -rw-r--r--  1 antkong  staff  604 26 Mar 09:44 Plan.js
  </code></pre>
  
  <p>How can I get rid of this message?</p>
  
  <p>I am using osx.</p>