Also the portion about how to close a connection does not only apply to
servers.

Issues adressed:
 - The actual data was never read from the socket, causing all even
   numbered loop iterations to fail
 - The socket variable was called server once

When a ZMQ_STREAM socket connection is broken (intentionally, via `shutdown()`
or accidentally via client crash or network failure), there is no way for the
application to dertermine that it should drop per-connection data (such as
buffers).

This contribution makes sure the application receives a 0-length message to
notify it that the connection has been broken.  This is symmetric with the
process of closing the connection from within the application (where the
application sends a 0-length message to tell ZeroMQ to close the connection).

Conflicts:
	CMakeLists.txt

- designed for TCP clients and servers
- added HTTP client / server example in tests/test_stream.cpp
- same as ZMQ_ROUTER + ZMQ_ROUTER_RAW + ZMQ_ROUTER_MANDATORY
- includes b893ce set ZMQ_IDENTITY on outgoing connect
- deprecates ZMQ_ROUTER_RAW

- REQ and REP sockets don't have HWM issues
- ZMQ_DONTWAIT applies to DEALER and PUSH only

contributors and doesn't reflect the real process. I've taken out all named
authors and referred to the contribution policy. Hopefully this will improve
the contributions to the man pages.

zmq::xpub_t::xread_activated() – change to process messages without 0
or 1 prefix, but without affecting subscriptions

zmq::xsub_t::xsend() – change to send rather than discard messages
without 0 or 1 prefix, but without affecting subscriptions

Update documentation

 - reverted commit 941be8d2.
 - fixed zmq_device implementation for latest socket_base class
 - added back zmq_device.3 man page

Signed-off-by: Martin Lucina <martin@lucina.net>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Pieter Hintjens <ph@imatix.com>
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Reaper thread destroys the socket asynchronously.
zmq_term() can be interrupted by a signal (EINTR).
zmq_socket() will return ETERM after zmq_term() was called.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

Signed-off-by: Martin Lucina <mato@kotelna.sk>

- Clarify ZMQ_LINGER, zmq_close (), zmq_term () relationship
- New socket options
- Clarify thread safety of sockets and migration between threads
- Other minor and spelling fixes
Signed-off-by: Martin Lucina <mato@kotelna.sk>

This reverts commit 77a3c36f.

Add some basic documentation for XREQ/XREP socket types, including
a brief description of the most common use case (REQ -> XREP) and (XREQ ->
REP).

* Fixed zmq_term, zmq_socket, zmq_close, zmq_setsockopt,
* zmq_getsockopt, zmq_bind, zmq_connect, zmq_send,
* zmq_recv, zmq_poll, zmq_device, zmq_stopwatch_stop
* Updated Reference Manual for these methods

* Added documentation for zmq_deviced, which we're developing
* Created consistent page footer in documentation template
* Page footer notes doc authors and copyright statement

Mostly Flow control and additions to zmq_socket(3)
Removed/changed lots of text regarding message queues
More fixes for 2.0.7 changes

Clarify pipeline and exclusive pair patterns