title: Date modified in file system does not change when switching branches in Git repo
body: <p>Can someone please help me understand why when switching branches with Git that the modified date in the Mac OS file system does not change?  For example, I have a file in repo called test.txt that is part of both the Master and Test branches.  </p>
  
  <p>In the master branch I edit and commit the file and then switch to the Test branch.  Since Git manipulates the file system, I would expect at that point that the date modified would change to the modified date of the version of the file in the active branch.</p>