title: Make messages i18n for specific directories or exclude directories
body: <p>My site structure looks like this:</p>
  
  <pre><code>project
  --apps
  ----app1
  ----app2
  --docs
  --templates
  ----module1
  ----module2
  ----module3
  </code></pre>
  
  <p>how can I run </p>
  
  <pre><code>django-admin.py makemessages --locale=en
  </code></pre>
  
  <p>on all apps and template dirs but leave out module1 and module3?</p>