Start adding the EPoller
Merge branch 'master' of github.com:OpenLightingProject/ola

Conflicts:
	common/io/DescriptorTest.cpp
	common/io/Makefile.am
	common/io/SelectServer.cpp
	common/io/SelectServerTest.cpp
	configure.ac
Merge branch 'master' of github.com:OpenLightingProject/ola
Fix handling of WriteDescriptors in the EPoller.
Clean up the Dmxter shutdown sequence so it works with the EPoller.
Merge branch 'master' of github.com:OpenLightingProject/ola
Default epoll to off, allow the OLA_USE_EPOLL env variable to control it in the
tests.
Fix the Epoller licences.
Default the log level in tests to INFO.
Make the tests pass with the select() implementation.
Fix a comment and a lint warning.
Fix a build error with the epoller.
Fix a memory leak in the new EPoller
Reuse EPollDescriptors.
Switch to using StringToBool
Avoid trying to use the EPoller on Mac.
Merge branch 'master' into epoll
Address Peter's comments from the code review.
Merge branch 'epoll' of github.com:nomis52/ola into epoll
Merge pull request #422 from nomis52/epoll

Add a new Poller implementation that uses epoll rather than select