revisit property and propertygui (and fix examples for msvc)
Merge branch 'propertyzeug' of https://github.com/hpicgs/libzeug into propertyzeug

Conflicts:
	include/propertyzeug/AbstractProperty.h
	include/propertyzeug/ValueProperty.h
	source/propertyguizeug/FilePathEditor.h
	source/propertyzeug/AbstractProperty.cpp
	source/propertyzeug/CMakeLists.txt