Fix bug 924347: Fall back to en-US download locale.

If no localized Fx build exists for the latest version
fall back to an en-US download link.
Merge pull request #1410 from pmclanahan/fx-download-broken-link-no-build-924347

Fix bug 924347: Fall back to en-US download locale.
Bug 935877 - Home page: enable VTCS for more locales

Added locales:
* VTCS: cy, is
 Bug 925278: add new locales to firefox/channel redirect

Added locales: hy-AM, zh-CN
Merge pull request #1413 from flodolo/morelocales_hp

Bug 935877 - Home page: enable VTCS for more locales
Merge pull request #1412 from flodolo/channel_morelocales

 Bug 925278: add new locales to firefox/channel redirect
Bug 779751: Newsletter updated only accept UUIDs for token.
Prevent tests from making network calls.

While fixing bug 779751 I found some tests that
were calling out to basket and salesforce. These
changes should mock all of that.
Merge pull request #1409 from pmclanahan/bug-779751

Bug 779751: Newsletter updated only accept UUIDs for token.
Update logo on Nightly firstrun page (Bug 939921)
Merge pull request #1415 from mozilla/bug-939921-nightly-firstrun-logo

Update logo on Nightly firstrun page (Bug 939921)
Careers teaser in comment and error console. Bug 937719.
Merge pull request #1411 from fwenzel/careers-teaser

Careers teaser in comment and error console. Bug 937719.