Make playlist sidebar scrollable.
Include default points of "0" for ExerciseLogModel, to avoid errors.
Only allow, and use by default, JSON in tastypie.
Related video links on exercise view working again.
Tweaks to frontpage styling and fix for search autocomplete dropdown.
Don't try writing exercise logs etc for non-logged in users.
Only show related video links for videos that exist.
Clear old messages when switching between entries in a playlist.
Display error message on quiz page when not logged in.
Tweaks to quizzes and tests.
Merge branch 'nalanda-rct2' of github.com:learningequality/ka-lite into backbone
Simplify sidebar entry template now that we have titles for all entries.