Zero config sorts & deduplicates showLangs & whitelisted

* showLangs parameter will be de-duplicated, while preserving order
* whitelistedLangs parameter will be de-duplicated and sorted in
the same order as showLangs, followed by alphabetically ordered
languages that are not in showLangs.

Change-Id: Id8b9221ed81cfdad70a6be837686a51242e690b9