Also modified component's receiver creation to be triggered on the first call to next, rather than iter.
This change means that the zmq context and socket for the component's receiver should always be created in
the same process as the consumer of the generator. Chaining together component wrapped generators will
result in the send process of the last component actually instantiating the receive socket of the prior component.
In this way, the components are actually communicating directly via zmq.
Component's send method now calls the wait_ready(), which waits for the monitor's GO message, inside
the generator loop. This guarantees that the generator's next method is called before the send loop blocks
on the monitor. As a result, components will call __init__ and next() without blocking, mimicking the
behavior of plain generators.
scottsanderson