jslint
Merge remote-tracking branch 'upstream/master' into jslint
remove extra comma
fix html
escape special character
correct common denominator for hints, fix #156905
Merge pull request #161345 from mauk81/patch-6

correct common denominator for hints, fix #156905
Merge pull request #161332 from mauk81/jslint

jslint
Merge pull request #161344 from mauk81/html

fix html
updated khan-exercise to fix dependencies in 'congruency' to add 'graphie-helpers' (more details in pull request)