Problem: insufficient unit tests for poller concept and ypipe

Solution: apply clang-format

Solution: fix shutdown of kqueue_t

Solution: use std::atomic only from VS 2015

Solution: use shallow_clone option instead of clone_depth

Solution: change order of appveyor build jobs to enable faster feedback
on more diverse builds

Solution: Increase test timeouts for poll poller under Windows

Solution: added documentation

Solution: add to list of sources

Solution: replaced by assertion

Solution: migrate test_sockopt_hwm to unity

Solution: extend output of wsa_assert

reuse

Solution: extract into functions defined in ip.hpp

Problem: signaler_t::make_fdpair not reusable

Solution: move make_fdpair to ip.hpp

Problem: epoll worker with no fds cannot be stopped

Solution: use interruptible epoll_pwait call

Problem: insufficient unit tests for poller

Solution: add test cases

Solution: set CTEST_OUTPUT_ON_FAILURE option

Problem: data races in select/poll poller implementations

Solution: fixed access to stale vector

Solution: change termination condition of select_t

Solution: remove stopping, stop on thread-safe conditions; add
additional checks for correct thread-safe usage

Solution: fixed call of select, and initialization of poll_t members

Problem: no test framework, no unit tests

* Problem: build failure with select as polling mechanism

Solution: cast mailbox_handle argument to (poller_t::handle_t) like in
the reaper thread class.

* Problem: build failure due to INT_MAX use without include

Solution: include limits and climits in src/select.cpp where INT_MAX is
used

* Problem: build failure due to unused variable in select.cpp

Solution: move the declaration of int rc inside the ifdef block where
it is actually used

* Problem: reference to wrong variable in select.cpp breaks build

Solution: fix it

* Problem: family_entry_t constructor has no body, build fails on *nix

Solution: add empty inline function in the struct

* Problem: no test coverage for poll and select

Solution: add Travis jobs for them on Linux

* Problem: Travis jobs cannot run in container infra

Solution: set sudo: false as it is not required anymore

Solution: use _snprintf when snprintf is not available

Solution: add it

Solution: add them to Makefile.am, linking to the static libzmq.a
library and its dependencies

Solution: add a noinst convenience static library and use it with the
tests that require it

Solution: add started flag

Solution: set up initial unit tests

Solution: extract thread_ctx_t from ctx_t

Solution: added MIT license file and github source info

Solution: use unity in test_security_curve

Solution: rewrite test_socket_null to use unity

Solution: add unity test framework, and integrate into cmake build

Fixed a deadlock and an assertion failure in poll_t

Solution: use wsa_assert instead of errno_assert

pollset entry

Solution: clean up retired entries before poll

Solution: fixed behaviour in corner cases

Problem: make format-check not implemented with autotools

Problem: DRAFT build broken with GCC 4.7

Solution: port implementation from zproject

Solution: change variable type in test_timers to match public API