title: phpDoc partial update
body: <p>I'm trying to automate documentation building in our team development environmen, so we decided to use phpDocumentor(2.7.0) and to trigger it to rebuild documentation on SVN post-commit.</p>
  
  <p>I have made a trigger, but I'm pretty shure that all documentation is rebuild every time it is executed, because even if I only commit one modified file, the phpdoc command lasts almost the same time like when documentation initial build.</p>
  
  <p>So my idea was to rebuild only documentation of those files, changed in the commit. Is there some possibility to do so ?
  I have looked into the documentation of phpDoc and Google, but nothing found.</p>