We currently have a bug about non-deterministic output in the MPD
generator. This works around that bug by optionally doing everything
in a single thread. This allows us to run manifest comparisons without
making the major changes needed to add that feature.
Issue #177
Change-Id: I10e1084dac77841220161fbd2575cdcb5c13c00e
Moved all code dealing with jobs into its own class so that the
packager code does not need to worry about initializing, running,
or stopping jobs.
Change-Id: I3e9ef1f22bd93d671f77d59ad15f23d1239078cf