Ssbench

* Fixed 29: Added support for Python 2.6 and cleaned up CentOS install
docs.

* Fixed 22: Added -k/--keep-objects option to keep all created objects
from a benchmark run.

* Update install docs with stupid Ubuntu install work-around.

* Try pinning pyzmq to 2.2.0 to fix reported install problems

* Fixed install bug by removing ssbench-qdrain from setup.py.

* Fixed 18: Replaced beanstalkd with ZeroMQ sockets

* Fixed 10: Added convenience spawning of ssbench-workers

* Fixed 20: Included a (simple) multi-box invocation example in README.

* Fixed up README installation instructions.