This bug is caused by fq which can terminate pipe before sending all
frames of a message first. So sometimes two messages were mixed and this
confused ZAP handler.

This patch just modifies one pipe parameter so that socket consumes all
messages before dropping the pipe.

This patch allows client applications to retrieve the remote endpoint from a message that originated from a tcp socket

As TIPC transport for 0MQ will only work on post 3.8
Linux kernels where nonblocking connect was added,
we add AC_RUN test to check for this functionality.
Should the test fail, tipc is excluded from build/test.
Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>

A ZeroMQ application can opt for TIPC based sockets
using the TIPC port name format:
zmq_bind(sb, "tipc://{type,lower,upper}");
zmq_connect(sc, "tipc://{type,inst}");

'type' is the service ID, and 'lower/upper' can be
used for service partitioning or basic load
balancing.

ZeroMQ TIPC transport requires a kernel >= 3.8
(nonblocking connect support for TIPC).
Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>

These were exposed to users, but have subsequently been removed as
sockopts. They are currently only being used by ZAP, so I've moved it to
a simpl function call (actually it's only used in one case even in that,
so there may be a further simplification possible there).

ZMQ_CONFLATE option is passed to pipepair() which creates a usual
ypipe_t or ypipe_conflate_t and plugs it into pipe_t under a common
abstract base.

- 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

Copyrights had become ads for Sustrik's corporate sponsors, going against the original
agreement to share copyrights with the community (that agreement was: one line stating
iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads
is also unfair to the many individual authors. I've removed ALL corporate title from
the source files so the copyright statements can now be centralized in AUTHORS and
source files can be properly updated on an annual basis.

Zeromq shall never send/receive socket identifiers for sockets in raw
mode. The existing implementation breaks this requirement after
reconnection.

- add unlikely hints
- drop unnecessary assertion
- style fixes

There is no need to require the 'more' flag in the provided message
structure be 0 when pulling message from the session.

    - Created a new option ZMQ_ROUTER_RAW_SOCK
    - Added new raw_encoder and raw_decoder to receive and send messages in raw form to remote client
    - Added test case file tests/test_raw_sock.cpp

    o To create a raw router sock set the ZMQ_ROUTER_RAW_SOCK option
    o ZMQ_MSGMORE flag is ignored for non-id messages
    o To terminate a remote connection send id message followed by zero length data message

Ref: https://zeromq.jira.com/browse/LIBZMQ-417

Significantly reworked the monitoring infrastructure with a more granular per socket API and to play well with monitoring endpoints in application threads

This patch introduces i_msg_sink and i_msg_source interfaces. This
allows us to make message encoder and decoder more general.

Compiling without warnings is a good goal, because it makes
new warnings (which probably indicate bugs) stand out rather
than getting lost in the spam.

My fixes fall into two categories:

    - Adding (void) casts of unused parameters, where their
      unusedness seems like a TODO (or in some cases a bug?).

    - Removing parameter names altogether, where the function
      is clearly a stub that will never use its parameters.

Should be no change in behavior.

There are three versions of monitor_event(), all taking
variadic arguments. The original code just has the first one
creating a va_list and passing that va_list variadically to
the second one... which creates a new va_list and passes it
variadically to the third one... and of course everything
blows up when we try to pull a non-va_list argument off the
stack.

The correct approach matches the C standard library's use
of printf/vprintf, scanf/vscanf, and so on. Once you make
a va_list, you must pass it only to functions which expect
a va_list parameter.

Fixes #415.

Rename the pipeset to terminating_pipes, as suggested by Martin H. Adds
asserts to test the pipe is contained in the terminating set where
appropriate.

This patch, salvaged from a trainwreck accidental merge earlier, adds a
new sockopt, ZMQ_DELAY_ATTACH_ON_CONNECT which prevents a end point
being available to push messages to until it has fully connected, making
connect work more like bind. This also applies to reconnecting sockets,
which may cause message loss of in-queue messages, so it is sensible to
use this in conjunction with a low HWM and potentially an alternative
acknowledgement path.

Notes on most of the individual commits can be found the repository log.

Revert "After speaking with Ben Gray and the discussion on the mailing list, this is an attempt to create a sockopt to allow connecting pipes to not immediately be available for traffic. The problem is in a PUSH to many PULL situation, where there is a connect to a PULL which is not there. This connect will immediately create a pipe (unlike bind), and traffic will be load balanced to that pipe. This means if there is a persistently unavailable end point then the traffic will queue until HWM is hit, and older messages will be lost."

This reverts commit fe3fb419.

Revert "Remove extra brackets as suggested by Martin H, and fix up a comment which was missing a word"

This reverts commit b79aaaf4.