New tight_tree search algorithm to reduce running time from |V|^2 to something closer to |V+E|.  May solve some old "trouble in init_rank" bugs.
New tight_tree search algorithm to reduce running time from |V|^2 to something closer to |V+E|.  May solve some old "trouble in init_rank" bugs.

ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz