Graph and UndirGraph concept modifications.

* For incidence iterators ({In,Out,Inc}EdgeIt) there is now baseNode and
runningNode functions in graph interface
* For Edge in undir graphs: Edge(UndirGraph const &, UndirEdge, Node)
constructor. Same for IncEdgeIt
* Edge(UndirEdge, bool) constructor is no more in the public interface. (But we
need it in the developpers interface).

AM_CPPFLAGS = -I$(top_srcdir)/src -I$(top_srcdir)/src/work  -I$(top_srcdir)/src/work/marci

noinst_PROGRAMS = graph-bench hcube bfs-bench

graph_bench_SOURCES = graph-bench.cc bench_tools.h

hcube_SOURCES = hcube.cc bench_tools.h

bfs_bench_SOURCES = bfs-bench.cc bench_tools.h