Added django-wiki's requirements to requirements.txt, because they weren't being included automatically.

updating dependencies for pystache, networkx, graphviz and removing redundant dependency for django-staticfiles

* need to be in mitx/ to install common/lib/*
* create data dir if it doesn't exit
* add a few more log messages
* Change url for our fork of django-pipeline to stop the hanging checkouts.
  It works either way on my machine, so not sure if this will fix it.