adder layers
New distance algorithm + node info flowTo

I put the nodes further to the right on the x-axis depending on the
distance. Cleaned up the code a bit, and the new flowTo info about
nodes, which prevents several arrows going back and forth between the
same nodes.
Tikz code revamped. Uses the new layer algorithm to calculate xy-coords and I have added some of the cases for the arrows that are to be made so that they are nicely rounded