graph_to_eps mission accomplished.
- lemon/graph_to_eps.h header created
- lemon/bezier.h: Tools to compute with bezier curves (unclean and undocumented
interface, used internally by graph_to_eps.h)
- demo/graph_to_eps_demo.cc: a simple demo for lemon/graph_to_eps.h

hier: hierarchygraph.h hierarchygraph_test.cc

	g++ -Wall -W -I../.. -I../klao -I../../lemon hierarchygraph_test.cc -o test

edge: edgepathgraph_test.cc edgepathgraph.h

	g++ -Wall -W -I../.. -I../klao -I../../lemon edgepathgraph_test.cc -o test