Added setting to notify teams of new videos hourly (#997)

Removed the webdriver testing from the default tests.  I was getting
import errors for some reason with it enabled.
add webdriver tests for message sending
make sure 1 email per member for each set of videos added
Adding missing migration
Merge branch 'gh-997' into gh-920
Removed the thumb_options paramater from S3EnabledImageField.

We aren't honoring that parameter anymore, so I removed it from the
options.

Added a bunch of empty migrations so that south updates it's tables
with the new spec for the field.