graph_io under construction
This is a working version, but needs more improvments.

todo:
documention + fix the file format
improve the exception system

add some possible asserts

tutorials

c LEMON max flow problem

p max 7 9

n 1 s

n 7 t

a 1 2 3

a 1 3 2

a 1 4 1

a 2 5 3

a 3 5 2

a 3 7 5

a 3 6 3

a 4 6 1

a 5 7 2

a 6 7 4