Asyncio2 doc improvements. Changed recvLine's behaviour.

recvLine had an edge case where it would return a partial line if the
socket were to be disconnected in the middle of a line being read. The
behaviour now is that the data is simply lost as it likely will be
unparsable by the protocol anyway.
Clean up IP address code in net module.
Copied most blocking socket operations to the net module.
Many renames. Created high level asyncnet module.