Solution: added to test_stream.cpp

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

I'm pretty sure this is an issue with the test being too picky and not a
bug, but the behavior in this situation is not well documented.

It's nice to be able to disable libzmq's internal timeout when there's
another timeout in the test runner being used which gives nicer error
messages.

I traced memory leaks found using AddressSanitizer down to these.

Fixed wrong message::init arguments.

Set the ZMQ_HEARTBEAT_TIMEOUT to default to the value of
ZMQ_HEARTBEAT_IVL if it's not explicitly set.
Change the units of ZMQ_HEARTBEAT_TTL to milliseconds in the API
and round down to the nearest decisecond so that all the options
are using the same units.
Make the maximum heartbeat TTL match the spec (6553 seconds)

This commit adds ZMTP connection heartbeats described in
http://rfc.zeromq.org/spec:37/ZMTP.

new allocation caused reference counters to lose track on copy

Problem: zmq_setsockpt() returns success when changing the
HWM after a bind or connect() even though the call has no effect.

Solution: Introduce a failing test a reminder we need to patch it.

Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.

Solution: specify these grants in the header of each source file.

When targeting a version of Windows less than Windows Vista, the
security tests fail to build. Added a check for Windows version
and substituted inet_pton for inet_addr. Fixes libzmq issue #1396.