Rids of angular-translate, closes item:308

Since we're *definitely* targeting Chrome, we might as well drop angular-translate and get locales support via `chrome.i18n` for free.

Since angular-translate is promised-based, we should see a slight performance increase.

Holding out with tests (for now) as this ties in with @m0t0r's work with chrome storage.

@futuresandwich, could you review and merge (if it passes review :wink:) soon rather than later as this is a huge diff.