Solution:
- Add check for the [count] parameter in zmq_sendiov() and zmq_recviov()
- Use and add test for zmq_sendiov() in tests/test_iov.cpp
- Add error state tests for zmq_sendiov() in tests/test_iov.cpp
- Add error state tests for zmq_recviov() in tests/test_iov.cpp
- Cleanup tests/test_iov.cpp for style, consistency and clarity
- Generally improve test coverage for both API methods

Hat-tip:
@somdoron, @bluca

problem: no documentation for Radio-dish and UDP

Problem: relicense statement from imatix is in the wrong place

Solution: move the statement to the folder introduced in commit:
dd51cad0

Problem: need to collect grants to relicense under MPLv2

Naos Ltd license grant/quitclaim

RELICENSE: Start collecting MPLv2 license grants

Problem: libzmq lacks a good doxygen config

Solution:
- Add Doxygen.cfg file to make it simpler for library users and interested
parties to view library internals/externals
- Add README.doxygen.md as an Overview for Doxygen-generated documentation

Notes:
This could later be added into CI for autogenerated documentation that could be
posted to the gh-pages branch.

Problem: unistd.h redundantly included twice

Problem: test_pub_invert_matching missing in autotools build

Solution: fix it

Solution:
- add it to Makefile.am

Problem: tune_tcp_keepalives signature more than 80 chars on a line

Problem: typos and trailing whitespace in code/comments

Solution: fix it

Solution: fix them

Solution: fix them

Solution: fix them

Problem: XPUB test broken since #1566 on Windows

Solution:
- Adjust test_xpub_proxy_unsubscribe_disconnect() to support different
  protocol types
- Exclude the IPC tests on Windows and OpenVMS

H/T: @somdoron

problem: no way to detect in czmq if timers class available

Solution: kick off process with grant from iMatix

problem: Tests are failing on windows

Problem: assertion in test_xpub_manual is swapped

Solution: check that both pointers passed as arguments to
test_missing_subscription are non-NULL, instead of the opposite.

Problem: XPUB test broken on Windows since #1569

Solution:
- Adjust test_subscriptions() to support different protocol types
- Run TCP and IPC tests everywhere but on Windows and OpenVMS

Fix unresolved external symbols for gather and scatter classes on MSVC 2010-2015.

Fix issue with unresolved external symbols for the gather and scatter classes by adding them to the MSVC 2010, 2012, 2013 and 2015 projects.

Problem: Windows IPC check broken (check_protocol)

Solution: Fix the preprocessor check from || to &&