Made create-admin easier to use from script.
Made create-admin easier to use from script.

* Password may be specified on the command line, via an environmental
  variable, or if neither can be used the user will be prompted.
* The create_admin.py script is now importable and the create_admin()
  function may be used directly from a python script or the python
  interactive interpretor.

ucrcsedept/galah,brownhead/galah,ucrcsedept/galah,brownhead/galah,ucrcsedept/galah,galah-group/galah,brownhead/galah,galah-group/galah,galah-group/galah