* Split EventListener into several internal subclasses. This fixes issue with multiple inheritance where each BaseClass.__init__() call would overwrite the previous one. This meant that you could only add EventListener to one type of event managers. * MapView now adds maps and layers to EventListener * LayerEditor should now fetch only NameClash exceptions when creating or editing layers

<Window title="Load Map">
	<HBox>
		<VBox>
			<DropDown name="mapList" min_size="100,0" />
			<Spacer />
		</VBox>
		<VBox>
			<Button name="okButton" text="Load Map"/>
			<Button name="closeButton" text="Cancel"/>
		</VBox>
	</HBox>
</Window>