Ssbench

* Fixed a few bugs/typos.

* Fixed 46: Use blocking calls where possible.

* Fixed 47: Allow batching of work jobs.

* Fixed 26: Add socket timeouts.

* Fixed 42: Support Keystone v2.0 auth.

* Fixed 39: Never set nofile less than 1024.

* Fixed 34: Never use concurrency < 1 for workers.

* Fixed 38: Allow -S while still authenticating.

* Fixed 32: Save results gzipped.

* Fixed 25: ssbench-worker will re-auth if necessary.

* Fixed 21; added ability to kill workers.

* Fixed 16: raise file descriptor limit if run as root.

* Fixed bug when using the scenario's user count.

* Actually install the sample scenario files, CHANGELOG, AUTHORS, and
LICENSE as "data files"

* Tweak CentOS install instructions to install gevent-zeormq as its own
step.