Bug 858797 - fx mozharness builds: affects clobberer/purge - uses base_work_dir over buildprops basedir, r=callek
bug 907890 - show commands being run for builds r=nthomas
Merge branch 'master' of https://github.com/mozilla/build-mozharness
Merge branch 'master' into build-cfg-integration
uses encode over str for uni conversion