Merge pull request #699 from code-dot-org/staging

update levelbuilder
Merge pull request #722 from code-dot-org/staging

updating levelbuilder with staging
Merge pull request #727 from code-dot-org/staging

merge staging into levelbuilder
Merge pull request #728 from code-dot-org/staging

add course 4 unplugged videos
Fix RTL callouts: flip left/right and reverse x adjustment
Right-align callout text for RTL callouts
Temporarily send en-US users to static frozen from code.org/learn.
Merge pull request #785 from code-dot-org/planbfrozen

Temporarily send en-US users to static frozen from code.org/learn.
Code.org homepage link to frozen goes to static version too.
make studio.code.org frozen also point to static frozen.
Merge pull request #787 from code-dot-org/planbfrozenhomepage

Code.org homepage link to frozen goes to static version too.
unwrap transactions on milestone post (for UserLevel, UserScript, and User)
fix test for disabling trophies
Internationalized text for map search.
added "learn" to the urls checked so the printing is better hid

This is implemented with document.referrer.
Merge pull request #792 from code-dot-org/staging

DTT to sync up the branches
Redis cache level_sources
Merge branch 'staging' of github.com:code-dot-org/code-dot-org into staging
Merge pull request #793 from code-dot-org/staging

DTT to sync up the branches
Go back to using real Frozen tutorial, not the static one.