Marble: Add support for the KML Link tag
completed by: Mayank Madan
mentors: Torsten Rahn, René Küttner, Dennis Nienhüser
Implement a GeoDataLink class and kml tag handlers for link and its child elements, see https://developers.google.com/kml/documentation/kmlreference#Link
Integrate it with the NetworkLink element from https://git.reviewboard.kde.org/r/108339/ and extend its test case.