title: Is it valid in subversion to branch a subfolder?
body: <p>I have a subversion project that have a repository and <code>trunk</code>, <code>tags</code>, <code>branches</code> top-level items. For this project, <code>trunk</code> contains a folders for a big parts like 'common', 'libs', 'core', 'help', 'install', 'tests' etc. The question: is it valid in subversion to branch <code>trunk/common</code> or do i need to always branch entire <code>trunk</code>?</p>
  
  <p>I have checked - all seems work fine while branching <code>trunk/common</code>, but TortoiseSVN don't show such branches in <code>revision graph</code> :(. This leads me to the assumption that it is not correct to branch something over than <code>trunk</code>.</p>