fix(client): Only send a `link_expired` event if the password reset link is expired.

fixes #1283
Merge pull request #1300 from mozilla/issue-1283-link-expired-event

fix(client): Only send a `link_expired` event if the password reset link...
chore(build): Remove mocha.html from usemin processing
Merge pull request #1302 from vladikoff/usemin-no-mocha

chore(build): Remove mocha.html from usemin processing
fix(tests): Fix throttled test. Fixes #1144.
Merge pull request #1303 from vladikoff/issue-1144-throttle-test

fix(tests): Fix throttled test. Fixes #1144.
chore(l10n): update string templates for train 16
Merge pull request #1307 from mozilla/update-strings-train-16

chore(l10n): update string templates for train 16
feature(server): Add a forwarding proxy for IE8.

* Proxy auth server requests when the url is prefixed with `/auth`
* Proxy oauth server requests when the url is prefixed with `/oauth`

fixes #102