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

EXTRA_DIST = sub_graph_wrapper_demo.dim

noinst_PROGRAMS = dim_to_dot sub_graph_wrapper_demo graph_to_eps_demo

dim_to_dot_SOURCES = dim_to_dot.cc

sub_graph_wrapper_demo_SOURCES = sub_graph_wrapper_demo.cc tight_edge_filter_map.h

graph_to_eps_demo_SOURCES = graph_to_eps_demo.cc