Port tests to windows and add to cmake build.
Fix up threading code from port tests to windows.
Merge branch 'master' of https://github.com/zeromq/libzmq
Fix running tests from cmake on linux.
Implemented zmq_send_const
Added zmq_send_const test
Fix doc typo
Merge pull request #625 from ulikoehler/zmq_send_const

Add zmq_send_const for constant data
Attempt to fix disconnect not respecting linger

Looks like linger is honoured properly, but shutting down the session
causes the pipe termination to come from that side - because the local
pipe then shuts down right away it seems to trigger a terminated on the
other end instead of waiting. This way we trigger the termination from
the local end and then terminate the session.
Merge pull request #624 from ricnewton/master

Port tests to windows and add to cmake build.
Merge pull request #627 from ianbarber/master

Attempt to fix disconnect not respecting linger