title: only fully recursive checkout includes externals
body: <p>I am checking out an SVN repository including externals (svn:externals property).</p>
  
  <p>But, apparently, if I use --depth with any value other than 'infinity', the externals are not downloaded. This is especially ironic, since apparently it is possible to update later with --set-depth exclude and exclude folders later.</p>
  
  <p>Is it possible to check out selectively <em>and</em> include all externals?</p>