First pass at CSV report output.

This doesn't quite address everything in issue #58 yet, so I'm not
closing it out.

Also updated the README in prep. for releasing 0.2.14.

Moved -q (--quiet) to top-level parser where -v (--verbose) lives.

Tweaked log formatting a little bit: got rid of log channel which was
always "root" and added timestamps for --verbose.

Got rid of a few hopefully-no-longer-needed debug-level logging
messages.
Fix bug in ssbench-master kill-workers; bump version to 0.2.15
Fix another bug in ssbench-master kill-workers; version bump to 0.2.16