title: Make a SVN working directory contain EXACTLY the same as a clean checkout
body: <p>For doing builds, packaging files up, etc, it's needed to have a completely clean version from SVN. There can't be any non-versioned files which are floating around, e.g test.png might get packaged up if all PNG files are grabbed.</p>
  
  <p>But, getting a totally new checkout is time and bandwidth consuming. So is there a way to take a working directory and get it to be <em>exactly</em> identical to a clean checkout, deleting non-versioned files as well as doing an svn update?</p>