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.

* remove hg data repo
* pull the 6.002x repo

added a posix compliant check to make sure you are using bash to run the script, added option to use --system-site-packages for virtualenv, updated the ending instructions on how to start the server