[lukepolo]

Relative times like "5 minutes ago" now read in the panel's language and follow a language switch; until now they were English in all 16 locales.

• TimeAgo picks its javascript-time-ago locale from the i18n locale (zh-Hans → zh, zh-Hant → zh-Hant, the rest by code)
• Only the language in use is downloaded, as a small chunk; English stays bundled and shows until that chunk arrives
• One formatter per language, shared by every TimeAgo; the shared minute and second tickers are unchanged
• A spec mounts TimeAgo in German, Portuguese and both Chinese scripts, and switches language on a mounted one