Merge master into prod

This will bring prod up to date, and will include the recent "Make Contribution" fix.

I ran this as an adhoc on Saucelabs and it passed [1], but haven't been able to run it on the local grid yet as it (the grid) is having issues.

[1] http://qa-selenium.mv.mozilla.com:8080/job/amo.prod.saucelabs.testing/1/