updated khan-exercises
new exercises added
don't hide summatives as orphans
show videos in class progress report
bug fixes on previous
css changes to make rtl menu arrows
class video progress links to videos
class progress report - video mode disables time-based filtering
updated text for video progress feature
optimized datastore access in video progress report
fixed html text for class progress

also created a separate legend for video progress
udate progress report legend for video/exercise
don't sync exercises with khanacademy.org
deployed new exercises
restored syncing of exercise display_name from file
bug fix in selecting videos for exercises
bug fix in displaying admin/edit view for summative exercises
content-admin - show left-to-right
fixed server side handling of adding related vids to exercise
bug fix on previous commit (dict->data)