Enable printf in unit tests regardless of DEBUG flag status.
Be more defensive when looking up signals in button event handler.
Merge branch 'next' into handler-tests
Add unit tests for button handler.
Add unit tests for door handler.
Merge branch 'next' into handler-tests

Conflicts:
	src/tests/log_mock.c
Add missing OSTYPE assignment in Makefile for OS X.
Merge remote-tracking branch 'origin/handler-tests' into next