Add failing test reproducing issue #1015.

There is a race condition when connect and bind on a new inproc
endpoint happen "simultaneously" in threads.  Causes the error:
  Assertion failed: ok (ctx.cpp:474)
Mark failing test for issue #1015 as XFAIL
Merge pull request #1046 from mrvn/pull-testutil-set-alarm

Set an alarm(60) in setup_test_environment() when not on windows so test...
Merge pull request #1047 from mrvn/pull-testutil-expect_bounce_fail-send-timeout

Add a send timeout in expect_bounce_fail()
PLAIN: Small simplification
Merge pull request #1048 from hurtonm/master

PLAIN: Small simplification
Problem: security tests block on zmq_send

The expect_bounce_fail () helper assumed that messages could always
be sent. However in some cases zmq_send() blocks, due to there not
being any outgoing pipe. This changed in 77f5f7, where previously
there would be a pipe that kept trying to reconnect forever.

Solution: use a send timeout and check for EAGAIN if sending failed.
Minor trim of man page title
Merge pull request #1049 from hintjens/master

Minor fixes
Small code cleanup

- add const modifier to address parameter of event generating functions
Merge pull request #1051 from hurtonm/master

Small code cleanup
Revert change to VS props references because of VS UI limitation.
Generalize dependency reference in GSL config/script.
Update VS version resource and package version.
Update NuGet packaging.
Code cleanup

- limit visibility of pending_connection_t
- add const qualifiers
Merge pull request #1053 from hurtonm/master

Code cleanup
Merge pull request #1054 from evoskuil/master

Minor updates to VS build configuration and NuGet packaging.
Fix race condition in connecting inproc sockets
Merge pull request #1055 from hurtonm/master

Fix race condition in connecting inproc sockets