This reverts commit 5e0facda.

This reverts commit 2a84d259.

Broke regression test on test_hwm.cpp.

Feature/divide by zero investigation

These changes cause an assertion in lb_sendpipe() when executing the test_security_plain testcase.

Provides control of race windows and logging for some of the interesting transitions.

Include ZMTP properties in message metadata

Metadata are built in stream_engine now.
This makes it easy to extend metadata with user-defined properties.

Don't add empty metadata to received messages

tweetnacl integration for curve

Conflicts:
	CMakeLists.txt

Add metadata to received messages

Bumped ABI version to 4.0.0

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=743508

The ABI in fact changed in two significant ways, one with inproc
connects, and one with socket monitoring

Solution: generate libzmq.so.4.0.0 library instead.

This change should be backported to zeromq-4.x

Allow to set up a source address and port for outgoing tcp connections in zmq_connect

Few examples:
tcp:://192.168.0.4:55555;192.168.0.254:1234
tcp:://192.168.0.4:0;192.168.0.254:1234
tcp:://eth2:55555;192.168.0.254:1234

Define i_properties interface

- copy and move message operations are updated to maintain proper
  reference count of properties object
- zmq_msg_gets updated to use i_properties interface to fetch property
  value
- setter/getter added to msg_t class

Update function prototype for zmq_msg_gets ()

Added modifiers reflect the following properties:
- zmq_msg_gets () does not mutate property parameter
- zmq_msg_gets () returns a pointer to memory the caller should not
  modify

Add pointer to properties into message structure

Various small cleanups

- additional messages to help people debugging security errors

Has some bits commented out due to #939, now work.

Note: there is an issue in libzmq when binding/unbinding or
connecting/disconnecting (I did not investigate deeper) the
same socket several times. Even closing the socket with zero
linger, zmq_ctx_term will block. The workaround in this test
case is to close the sockets for each test step.

- also removed deprecated man pages from Makefile
- they remain in repository for reference

Windows build/packaging updates.

Cleaned up socket monitor code, tests, and man page

Specifically:

* zmq_event_t should not be used internally in libzmq, it was
  meant to be an outward facing structure.

* In 4.x, zmq_event_t does not correspond to monitor events, so
  I removed the structure entirely.

* man page for zmq_socket_monitor is incomplete and the example
  code was particularly nasty.

* test_monitor.cpp needed rewriting, it was not clean.

Fix windows non-unicode build

update ZMQ_STREAM docs about connection notification