Allow LWR runner to publish/consume messages via message queue.
To use LWR via message queue, ensure each such destination defines "default_file_action" as "remote_copy" and the LWR base staging directory pointed to by the  "jobs_directory" parameter. Finally add a "url" argument to LWR job runner plugin in job_conf.xml specifing the amqp URL to target (by default this will target the default ("_default_") LWR job manager - this can be overridden by specifing a "manager" attribute the plugin element in job_conf.xml).

Some of the implementation details here are bit hacky now to localize changes to LWR, once Dannon has merged his work - a new job runner base class or option should be implemented to account for this truely asynchronous job running implementation. (Comments inline about this.)

This updates the LWR client through LWR changeset 59ad1ea03448.