Remove CSRF middleware/processor in aws and dev settings,
not common.  This ensures that we load the MITX_FEATURES
token BEFORE deciding to disable CSRF.
Moved CSRF override into its own settings file
Removed check for AUTOMATIC_AUTH_FOR_LOAD_TESTING because
it's already implied that you're using load testing settings.
Added pylint exceptions to load test settings.
Merge pull request #548 from edx/will/fix-auto-auth-csrf-2

Ensure auto-auth feature flag actually disables CSRF