Interface for layers that allow snapping. Note that to make snapping work, all painters and
editors of the layer need to support snapping. Please refer to
ILcyMapComponent.getSnapList() to see how this interface is used.
Sets the snappable state. Note that this method needs to fire a
property change event whenever the "snappingOn" property changes its state.
Note: refer to
Implementing Bound Property Support Within a Bean
for an example about firing a property change.
aSnappingOn - True if snapping is to be enabled, false otherwise