Functions  
void  abstractMixedGraph::Layout_KandinskyTree (TNode root=NoNode, TFloat spacing=0.0) throw (ERRejected) 
bool  abstractMixedGraph::Layout_HorizontalVerticalTree (TNode root=NoNode, TFloat spacing=0.0) throw (ERRejected) 

Draw a binary tree bendfree in the small node orthogonal model.
The root node is defined by the predecessor labels if those exist, and then must the unique node without a predecessor arc. If no predecessor labels are at hand, a BFS search from the given root node is performed. If this is undefined, a degree 2 node is determined or, if nonexisting, a degree 1 node, and used as the BFS root. The tree is exported by the predecessor labels then. 

Draw a rooted tree in the onebent Kandinsky model.
