Johnson's Algorithm For All Possible Cycle

algorithm :: johnson's algorithm (improved by hawick & james) for
finding all possible cycle in any graph
runtime   :: O ((N + E) (C + 1))
source    ::
"http://blog.mister-muffin.de/2012/07/04/enumerating-elementary-circuits-of-a-directed_graph"
tested    :: no
Aligned Some Lines