title: How do I create a readable diff of two spreadsheets using git diff?
body: <p>We have a lot of spreadsheets (xls) in our source code repository.  These are usually edited with gnumeric or openoffice.org, and are mostly used to populate databases for unit testing with <a href="http://www.dbunit.org/" rel="noreferrer">dbUnit</a>.  There are no easy ways of doing diffs on xls files that I know of, and this makes merging extremely tedious and error prone.</p>
  
  <p>I've tried to converting the spreadsheets to xml and doing a regular diff, but it really feels like it should be a last resort.  </p>
  
  <p>I'd like to perform the diffing (and merging) with <code>git</code> as I do with text files. How would I do this, e.g. when issuing <code>git diff</code>?</p>