- BFD/DFS/Dijkstra compile test is done with skeleton::GraphSkeleton graph
and skeleton::ReadMap.
- 'skeleton::' is explicitely written instead of 'using namespace ...'
in graph_test.cc
- Output messages of type "makeRep(3)..." in unionfind_test.cc have been
changed in order not to confuse compiler output parsers.

 ./preflow_demo_leda < $1

 ./preflow_demo_boost < $1

 ./preflow_demo_jacint < $1

 ./preflow_demo_athos < $1

 ./edmonds_karp_demo < $1

 ./edmonds_karp_demo_alpar < $1

 ./edmonds_karp_demo_boost < $1