Refactoring: reduced dependencies.
Decouple touch screen interface from responsive graphics element.
Merge conflicts
Correct magnetic variation correction logic for $xxAPB output sentence.
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN into mainline

Conflicts:
	include/options.h
	src/chart1.cpp
	src/chcanv.cpp
	src/navutil.cpp
	src/options.cpp
	src/routeman.cpp
	src/toolbar.cpp