Use human appropriate values for bytes in log downloader
Use human appropriate values for bytes in log downloader

Also report the current transfer rate in the currently downloading status to help expose regressions in performance.

Hunter522/qgroundcontrol,RedoXyde/PX4_qGCS,kd0aij/qgroundcontrol,RedoXyde/PX4_qGCS,ethz-asl/qgc_asl,CornerOfSkyline/qgroundcontrol,ethz-asl/qgc_asl,CornerOfSkyline/qgroundcontrol,ethz-asl/qgc_asl,ethz-asl/qgc_asl,CornerOfSkyline/qgroundcontrol,kd0aij/qgroundcontrol,RedoXyde/PX4_qGCS,ethz-asl/qgc_asl,kd0aij/qgroundcontrol,CornerOfSkyline/qgroundcontrol,CornerOfSkyline/qgroundcontrol,CornerOfSkyline/qgroundcontrol,Hunter522/qgroundcontrol,kd0aij/qgroundcontrol,Hunter522/qgroundcontrol,RedoXyde/PX4_qGCS,Hunter522/qgroundcontrol,Hunter522/qgroundcontrol,kd0aij/qgroundcontrol,Hunter522/qgroundcontrol,kd0aij/qgroundcontrol,RedoXyde/PX4_qGCS,RedoXyde/PX4_qGCS