Merge pull request #880 from code-dot-org/delivered

deploy to production
Merge pull request #935 from code-dot-org/delivered

Deploy to production
Merge branch 'delivered'
Merge pull request #1042 from code-dot-org/delivered

Deploy to production
Merge pull request #1046 from code-dot-org/delivered

Delivered into master
Add support for hint visibility experiment.
levelbuilder changes
levelbuilder changes
levelbuilder changes
convert all move/turn/repeat blocks in custom levels to constant blocks
Fix URLs for new courses
Fix test hostname
Automatically built
levelbuilder changes
Use shorter test for artist category run test
Little hack to multi/match pre-dialog so that title & instructions are pushed to left if there's no image.
Set up course3 survey link.
Temporarily skip feedback test failing on test environment
- Add ability to skip tests by annotating with @skip
Fall back translations in unplugged pages
- Add helper for returning nil rather than error message on missing translations
Use more generic, raise/rescue `try_t` helper