Refactor stats so they do not pull in variables from sprout
Take latest cpp-common
Stats tool changes
Stopwatch tests
Experimental time control changes
Merge remote-tracking branch 'origin/master' into stats_refactor
Make stopwatch tests completely control time
Take latest cpp-common, and delete the sprout test interposer
Temporarily back out stats script changes
Markups
Merge pull request #367 from Metaswitch/stats_refactor

[Reviewer: Matt][From: Alex] Sprout changes following cpp-common stats refactor.