title: How to automatically remove unused gettext strings?
body: <p>I have a web application where I have several translations using gettext.  But now I have done a major rewrite of the application and while most of the strings are the same, there are also quite a few that were changed significantly or removed.</p>
  <p>I use xgettext to create the .po files and it's great to be able to find new strings in the code and add them to the .po files, but I don't see an option to remove strings that aren't found in the code.</p>
  <p>Is there an automated way to remove the strings from the .po files that are no longer in the code?</p>