Add basic Wikipedia Zero support for iOS.

* Ready for review.
** Once toast/alert approach app-wide is determined, this code should use that approach.
** Once i18n approach resolved, this code will possibly need to be updated to reflect that.
** As production release nears, devmode option should be removed and listeners updated.
* The iOS version does not use a background process for monitoring radios. This isn't a music/nav app.

Change-Id: Ie15e3e7dcb955f4fad9fbe3ebe1ddcbebe8a7332
Merge "Add basic Wikipedia Zero support for iOS."