IMPORTANT: Fixed very severe issues in clone operation of various
FGEStyle. Vector of observers was not duplicated, but instead was
referenced from both original object and clone. Eventually, removing an
observer from one side also removed from the other side. This lead to
notification not being properly forwarded to GR's and in turn to Views.
Conflicts:

	flexodesktop/GUI/flexographicalengine/src/main/java/org/openflexo/fge/graphics/BackgroundStyle.java