MapSourceDesc: Add missing include

	* Include map-source.h to access MapProjection enum.
Label: Fix create constructor

	* Remove add_actor() in Label::create(const std::string & filename)
Tile: Remove parameter in set_content()

	* Remove bool fade_in parameter in set_content()
View: Fix various compilation issues

	* Remove ScrollMode enum.
	* Remove get/set_scroll_mode() methods.
	* Remove ::scroll-mode property.
	* Comment out ensure_visible() method due to
	unavailability of ChamplainBoundingBox.
Point: Make Point inherit from Object

	* Point is no longer a boxed type but a class
	inheriting from Glib::Object.
PathLayer: Rename Polygon to PathLayer

	* Rename class name and methods in path-layer.hg
MarkerLayer: Rename SelectionLayer to MarkerLayer

	* Rename class name and methods in marker-layer.hg