Revert "graph: rolled back the changes, since they break something with boost 1.55"

This reverts commit 734e1920f59b9dc79762592928eae1483d3b1ff7.
graph: reverted the roll back; replicated BOOST_GRAPH_NO_BUNDLED_PROPERTIES directives in best_path() and restored node as const node_t& to graph[target] in best_path()