Added code to use django Auth groups to manage permissions.
Addresses issue #218
Added ability to delete experiment configuration.
Fixes Issue #226
Created a Django Management Command called assignpermissionsgroup to assign current users to proper permissions group.
adding AuthGroup creation to tests, account profile test is still failing however as /dashboard/ isn't redirecting to
/account/profile for some reason in the test
fixing tests, setup_test_participants now creates demo participants who don't need to be redirected to the account
profile to fill out profile info when visiting /dashboard with an incomplete profile.