* Changed update method so output layer nodes are organized according to their position in the output layer.
* Made convenience plotting method static
* Rewrote updates method for more convenience. Plotting function and intervals can now be specified. Number of iterations over input data can now be specified.
* Modified decay function of neighborhood size so it reaches ~0 when the last input is fed through. Probably still needs more tuning.
* TODO: Improve speed of algorithm. Finding the BMU naively is expensive, and updating every node with every pass through is also expensive.