1.0.5 new flags: `-json`, `-runs`, `-iops-duration`

We've added JSON output as an option (-json).

We've also added the ability to specify N runs (e.g. -runs 5). This is useful for gathering a large dataset.

And finally, for rapid testing, we added the -iops-duration flag. Sometimes the fifteen-second default is too long: -iops-duration 0.5