Correcting the structure of the graph's and adaptor's map.
The template assign operators and map iterators can be used for adaptors also.

Some bugfix in the adaptors

New class SwapBpUGraphAdaptor which swaps the two nodeset of the graph.

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