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.
Implicit registration of an fd now only occurs when a new socket is
created (in socket() or accept()). This makes the implementation much
simpler, changes to the linux version will follow.
Reworked detection of a file descriptor being closed with epoll (in the
case of sockets it is when the remote host disconnects). Ensured that
events are only updated when they change.
When using MSG_PEEK and data is retrieved ``lpNumberOfBytesRecvd`` will
not be set to the number of bytes read by WSARecv. The buffer must
therefore be checked to ensure it's empty when determining whether
``recv`` shall return "" to signal disconnection as we want to read as
much data as has been received by the system.
