Modify auto_auth to accept parameters for overriding created user attributes.
Rename MITX_SETTING AUTOMATIC_AUTH_FOR_LOAD_TESTING -> AUTOMATIC_AUTH_FOR_TESTING because it will be used for acceptance testing also.
Modify lms acceptance test to use auto_auth.
Modify cms acceptance tests to use auto_auth workflow.
Merge pull request #608 from edx/zoldak/auto-auth-acceptance

Auto auth can now accept parameters for user attributes.