Defer loading of progress view and submit button till user data loaded.
Fire event when exercise view is ready for another exercise to be loaded.
Fetch exercise log via collection, and then load progress view.

Also, don't load progress view if user isn't logged in.
Merge branch 'backbone' of https://github.com/rtibbles/ka-lite into backbone
Rename "random_seed" to "seed" on AttemptLog model.
AttemptLog loading/saving/display working on Backbone exercise page.
Return a timezone-free string from statusModel.get_server_time
Update ExerciseLogModel in parallel with AttemptLogModels.
Fixed tastypie permissions issues for users/groups, to restrict access.
Tweak to URL for exercise data endpoint, to allow dots in exercise IDs.
Response log tracking on attempt logs and hint interface/tracking fixes.
Fixed race condition: statusModel-dependent toggling waits for page load.
Implement working TestResource API endpoint.
Start and stop templates for Student Tests.
Interim commit for TestModel changes.
Merge branch 'backbone' of https://github.com/jamalex/ka-lite into backbone
Implement first pass of TestLogModel.
Add seedrandom.js