Partway through integrating Perseus rendering into Backbone views.
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Exercises rendering again, and proceeding to next question.
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Merge branch 'hackathon' of github.com:learningequality/ka-lite into hackathon
Progress saving/loading working on Perseus exercises.