Only count the first click of the "hint" button as an attempt.
Don't make unnecessary /api/v1 requests from khan-exercise.js
Merge branch 'release-0.10.0' of github.com:learningequality/ka-lite into release-0.10.0
Merge branch 'release-0.10.0' of github.com:learningequality/ka-lite into release-0.10.0
Added build number.