Use xmleql in the KML tests

This also involves some modifications to the xmleql functionality now that
it was tested with a real-life case (KML). Also, some of the input KML files
needed to be changed since we currently cannot roundtrip 100% of the input.
Merge pull request #699 from bartvde/kmlxmleql3

Use xmleql in the KML tests (r=@ahocevar)