Fixed accessibility labels are not always created in problems.
STUD-1524
Correcting JSON
fixed JS link and add contributor guidelines to change log
Merge pull request #3520 from edx/markhoeber/documentation/devdoc-changelog

added contributor guidelines to change log
crude fix for intermittent jasmine test failures
lti 2.0 result service rest endpoint
Merge pull request #3526 from edx/jsa/jasmine-fix

crude fix for intermittent jasmine test failures
Merge pull request #3519 from edx/han/json-lint

Small JSON correction
Merge pull request #2685 from edx/jbau/lti-20-outcomes-rest

LTI 2.0 results service endpoint
Documents in data packages are in raw format, not compressed or minified
Merge pull request #3521 from edx/ahodges/documentation/DOC239

Documents in data packages are in raw format, not compressed or minified
Merge pull request #3451 from edx/waheed/stud1524-accessibility-labels-missing-in-problems

Fixed accessibility labels are not always created in problems.
Merge branch 'master' of https://github.com/edx/edx-platform into clytwynec/update-bok-choy-setup-tasks-prereqs