Added several related messenger features: non blocking mode, pn_messenger_work, pn_messenger_interrupt, optional arg to pn_messenger_send. Also added basic non blocking smoke test for messenger in ruby and python. These address PROTON-231.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1502346 13f79535-47bb-0310-9956-ffa450edef68
PROTON-349 - Added name accessor for pn_connector_t


git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1502372 13f79535-47bb-0310-9956-ffa450edef68