Various modifications to enable fast multiplexed communications.
Various modifications to enable fast multiplexed communications.

 * Added ZMQ context to agents to allow running in threads w/o conflict.
 * Use copy=False to enable sharing buffers when moving between sockets.
 * Added BaseAgent class.

schandrika/volttron,schandrika/volttron,schandrika/volttron,schandrika/volttron