Solution: added test case

Solultion: clarify that notifications for unique subs/unsubs are always
passed, and these option only affect the behaviour for duplicated ones.

Solution: add test_xpub_verbose to cover those APIs

Solution: introduce a type template argument

Solution: added further test cases

Solution: added some TODO comments, improved existing documentation

Solution: added test case, reduced code duplication in tests

Solution: added unit test and assertions

Solution: add test case

Solution: added some test cases for rm

Solution: added test case

Solution: add CODE_COVERAGE_*FLAGS to unit tests build

Fixes #2949

Solution: add some more test cases

Solution: made mtrie generic (to remove complex dependency on pipe_t),
and added some unit tests

Solution: add const, introduce typedef

Fix gcc 8 build warning/error with -O3.

Problem: No support for addressing using TIPC Port Identity

ZeroMQ currently supports location independent addressing using TIPC
Port Names with tipc://{type,instance}. This commits adds support for
connecting and binding using TIPC Port Identity addresses. To connect
using Port Identities the expected format is tipc://<Z.C.N:Ref>, e.g.
"tipc://<1.2.3:123123>". To bind using TIPC Port Identities the expected
format is "tipc://<*>".

Problem: race condition in unittest_poller

Minor fixes for windows cmake build

This fixes an error with the cmake install configuration, which
attempted an invalid copy of a .pdb file on windows, when the
BUILD_SHARED option is disabled.

This adds a new cmake build option called BUILD_TESTS, that can be used
to enable/disable building of the tests. This is enabled by default.

This updates the cmake set_target_properperties usage, so that the suffix
is specified for the MinSizeRel build type.

Solution: fix order of statements in test_events_t

Fix build break when SIO_LOOPBACK_FAST_PATH is not defined (i.e. in VS2010)

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