batch add new users

[pironej]

for instance, some way to go from a class list rather than having to add 17 students in individually!

[solomonr]

will need to create an admin manage.py command for this

it will read a CSV file and then do something like:

from django.contrib.auth.models import User
new_user = User.objects.create_user('username', 'email', 'password')