to avoid overflow for large messages

send/recv still succeed for large messages,
but `zmq_msg_size` must be used to get the true size.

found.
Solution: Include the source directory

Problem: _sleep is a library function of Windows.
Solution: use sleep_

Current ZMQ_REQ_RELAXED test improvement to check that pipes are not closed
after executing two send() in a row with no recv() in between.

These sockets don't handle multipart data, so if callers send it,
they drop frames, and things break silently.

Solution: if the caller tries to use ZMQ_SNDMORE, return -1 and
set errno to EINVAL.

Solution: change zmq_poller_close(p) to zmq_poller_destroy(&p)

If we're going to add CLASS-like APIs we should use the proper
syntax; specifically 'destroy' instead of 'close', which is a
hangover from the 'ZeroMQ is like sockets' model we're slowly
moving away from.

Solution: change zmq_timers_close(p) to zmq_timers_destroy(&p)

VMCI transport allows fast communication between the Host
and a virtual machine, between virtual machines on the same host,
and within a virtual machine (like IPC).

It requires VMware to be installed on the host and Guest Additions
to be installed on a guest.

Solution: add test case

These sockets deal only with single part data (at present), so the
drop tests are misleading / inappropriate.

Solution: remove them.

These tests connected CLIENT and SERVER to DEALER... this isn't
allowed. I changed to CLIENT-to-SERVER in both cases. The result
was aborts in client.cpp and server.cpp which cannot handle
invalid multipart data.

I removed the asserts in each of these in xsend.

Solution: fix the test cases and remove the (unwanted?) asserts
in client.cpp:xsend and server.cpp:xsend.

Solution: fix to use CLIENT-to-SERVER and increase number of messages
sent to 100K per thread, to better stress thread safety.

This is due to the mangled include of platform.h, which was to make
CMake happy.

Solution: in CMakeLists.txt, define USING_CMAKE and then look for
platform.h in current directory if that is defined, else look in
../src/ as one would expect.

We do not use 'get' for getters.

Solution: rename to zmq_msg_routing_id () for public API.

Tests were failing, because some deque calls were causing undefined
behavior: calling front() or pop_front() on an empty deque. Such
calls are now safeguarded.

The patch fixes the issue #1568.

The patch fixes lingering subscriptions that occur upon disconnection
on XPUB sockets with option XPUB_MANUAL when used in a XPUB-XSUB
proxies.

Solution: Convert to spaces and remove trailing whitespace in these files.

Solution: added to test_stream.cpp

Under linux 3.16.0-4-amd64, I was getting occasional test failures
before fixing this.