mozharness docs: http://escapewindow.com/mozharness/
Production use of mozharness will use mozbase packages from an internal pypi: http://puppetagain.pub.build.mozilla.org/data/python/packages/
(from https://wiki.mozilla.org/ReleaseEngineering/PuppetAgain/Python )
* mozprocess (basic low level process management)
** subclass popen
*** open
*** poll
*** kill
*** wait
*** stdout
*** pid
** readWithTimeout
* mozfile (os file i/o managemenet)
** copyfile
** removedir
** makedir
* mozlog (log file management)
** write
** init