pull off job start/stop time after job completes
add getter functions so start and finish times are saved
add explanitory code comments, handle getStartTime() returning zero, and remove commented out code
show each m/r job's total duration
include moment lib
make sure time parts formatted with two digits
Merge pull request #16 from mortardata/mroddy_track_job_start_stop

Track M/R Job Start/Stop Time and Show Total Duration