Bug 966674: #1 Clean up a couple of ReferenceErrors; r=gps
Bug 966674: #2 Move exceptionStr() and stackTrace() from utils.js to Log.jsm; r=gps,rnewman
Bug 966674: #3 Add parameter substitution in log messages; r=gps,rnewman
Bug 900954: Expose addons.json flush to test harness; r=felipe
Bug 988292: Avoid main-thread IO for {profile}\addons.json; r=felipc@gmail.com,r=irving