First implementation of a composite figure: Raft

draw2d.shape.composite.Raft figures are shapes, which aggregate multiple figures. It works like a real raft. Aboard figures are moved if the raft figures moves. Draw2D differs between WeakComposite and StrongComposite. A raft figure is a weak composite and therefore the raft didn’t receive any notifications about drag&drop nor knowns the a boards figures anything about the parent composite figure.