title: Delete all untracked files from TeamCity working copy as part of checkout from SVN
body: <p>In our setup, TeamCity builds a Visual Studio solution, checked out by a SVN VCS root. The build process leaves some generated content in the working copy that TeamCity checked out (.dll's transformed .config files and such), and this is causing trouble.</p>
  
  <p>My solution to the problem is to enable "<em>Clean all files before build</em>" under checkout settings. This is not optimal, as i slows down the build process significantly.</p>
  
  <p>I've come across an option in the VCS root to "<em>Revert before update</em>", but <a href="http://confluence.jetbrains.net/display/TCD65/Subversion" rel="nofollow">the documentation</a> clearly states, that this will only revert tracked files.</p>
  
  <p>Is there a way that I can have TeamCity delete all untracked files from the working copy, as part of the checkout process, before building the solution?</p>