Backed out changeset 6a23d4536079 (bug 851338) because of Android test failures
Bug 850713 - Bump the required NDK version to 9. r=blassey.bugs,mh+mozilla
Bug 698328 - Add a new cubeb backend based on AudioTrack.cpp. r=kinetik
Bug 851149 - Fix cubeb_sndio build after switchable-backends landing.  r=kinetik