Bug 1038843 - Part 1: Land initial stumbler Java code and manifest fragments. r=nalexander,rnewman

The stumbler is a geolocation data collecting and uploading service.

This code is a partial export of the MozStumbler repository hosted at
https://github.com/mozilla/MozStumbler.
Bug 1038843 - Part 2: Enable stumbler based on existing 'app.geo.reportdata' Gecko pref. r=nalexander