- 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