Some examples lack license header

Some examples do not have license headers for the used .cpp files.

Apparently the files ./helloworld-qt/main.cpp ./helloworld-minimal/main.cpp ./helloworld-complex/src/main.cpp ./helloworld-complex/src/foo.cpp ./helloworld-complex/src/specialfeature.cpp lack them.

Would be nice if you could clarify this since i need to set a license for my examples - subpackage