Support XPub socket send last value caching to last subscription pipe with ZMQ_XPUB_MANUAL_LAST_VALUE. (#3511)

* Add ZMQ_XPUB_MANUAL_LAST_VALUE

* Surpport xpub send last value caching to one pipe with ZMQ_XPUB_MANUAL_LAST_VALUE

* Add test_xpubub_manual_last_value

* Add relicense and doc

Solution: libm and libsocket have to be linked explicitely

Solution: remove and add where needed

Solution: move test utilities to separate testutil library

Solution: migrate to Unity

Solution: migrate to Unity and separate test_security_no_zap_handler

This reverts commit ac19d5f4.

Solution: add test case run with cap_net_admin
Fixes #3397

Solution: define UNITY_SUPPORT_64 to force 64 bit support

Solution: move general monitoring test utilities to new testutil_monitoring

Add new HWM tests and more detailed documentation

- Lowercase all commands
- Unify indent to 2 spaces
- Remove spaces around brackets
- Remove repitition of condition in else(...) and endif(...)

Note: (re-)running CMake did not change the content of the generated files

Solution: merge into a single test_use_fd and reduce code duplication by extracting common functions

Problem: test program test_unbind_inproc is redundant, the same is already tested in test_inproc_connect

Solution: remove test_unbind_inproc

Use ZeroMQ_SOURCE_DIR, ZeroMQ_BINARY_DIR instead of CMAKE_SOURCE_DIR, CMAKE_BINARY_DIR in tests/CMakeLists.txt
Similar reason to change unittests/CMakeLists.txt

* Add ZMQ_ROUTER_NOTIFY draft socket option

Solution: add some msg helpers to parse commands, and check for
subscribe or cancel commands and process them accordingly in the xpub
and xsub classes.

Solution: guard CMake statement properly

Solution: specify not to use stdint.h for VS<=2008, fixes #3025

Solution: fix indentation

Solution: increase timeout

Solution: increase timeout, remove timeout settings for unsupported poll poller

Solution: check more socket type to cover other session managers.
Increase timeout as the test now takes ~12 seconds.

Solution: migrate to unity, merge into test_radio_dish, and split up test cases

Solution: add appropriate definitions to build

Lets the application set per-connection metadata.
Metadata is specified as "X-key:value" and set using zmq_setsockopt, eg:
zmq_setsockopt (s, ZMQ_METADATA, "X-key:value", 11);

The peer can then obtain the metadata from a received message:
char *data = zmq_msg_gets(msg, "X-key");

Solution: migrate to unity

* Problem: TIPC availability check is too strict

Solution: at build time only check if the API is available. In the tests
do a first check and a skip if the functionality is not available.

TIPC needs an in-tree but not loaded by default kernel module, tipc.ko
to be loaded, which requires root, so it is unlikely to be available on
any build system by default.
This will allow most distributions to ship with TIPC support built in,
and to avoid tests failure if the module is not there.

* Problem: no Travis tests for TIPC

Solution: mark one job with sudo: required and load the kernel module

* Problem: CMake fails when test returns 77 (skip)

Solution: set property to let it mark the test as skipped as intended

* Tests for different TIPC address types and code cleanup

* Adds tests for binding/connecting with different TIPC address types
  using Unity
* Adds error checking for address type misuse

Solution: add test_xpub_verbose to cover those APIs

Solution: Increase test timeouts for poll poller under Windows

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

Solution: build all the objects separately before the link step, to
avoid rebuilding when doing both static and shared builds

Solution: don't redefine preprocessor macro if it's already defined in
platform.hpp

Solution: Don't unlink file on close

File may not belong to the socket at that point.

Solution: when a connection breaks and ZMQ_RECONNECT_IVL is set to -1,
which means a reconnection will not be attempted, send a message from
the I/O thread to the application thread to make the socket call
term_endpoint, which is the equivalent of manually calling
zmq_disconnect.
This way subsequent zmq_connect call to the same endpoint will attempt
again to do a connection.
Otherwise, for some socket types like SUBs, those new connects will
fail as the endpoint is recorded, despite the connection having been
permanently closed.

Add test cases to exercise this corner case with TCP and IPC.

Solution: remove redundant target_sources directive

Soluton: added tests

Solution: enable test