removing node-duplicates in the decision-graph

Now using a hash-map to store the graph with the key-value of the
boardArray as one Integer. This helped avoiding the merging of clusters.
Now i am just testing if a node is already there - if so just add an
additional edge, otherwise add a new node and an edge.
Now i can create graphs (i can no longer say tree because nodes can have
more then one parent now because of the "merging of duplicates") where
each node is unique. I will add some neat yEd-screenshots in #9.
But still... no ACTUAL decision-making process. This HAS to come next -
no more hiding behind optimizing the tree/graph ;)