Implement first Pulsar Runner.

This runner the PulsarLegacyJobRunner - has all of the old defaults that the LWR runner had. Goal is to add new runners with better defaults for newer options to ease configuration.

LWR runner and client remains in Galaxy as is and can continue to target old LWR server. But these should be considered deprecated and will likely be dropped at some point. Its documentaiton in job_conf.xml.sample_advanced has been replaced with Pulsar documentation.

Pulsar runners will need to target a Pulsar server (now with a RESTful web interface - MQ option also available). Information on upgrading LWR to pulsar will be found on http://pulsar.readthedocs.org once Pulsar finds a home (WIP in progress on this doc here: https://github.com/jmchilton/lwr/blob/pulsar/docs/source/upgrading.rst).