Other arguments passed on to discrete_scale to control
name, limits, breaks, labels and so forth.
pokemon
An integer or character pokemon name
spread
How many, quite distinct, colours should be returned. See details.
Details
If spread is given an integer, the full palette is
clustered into that many groups (ward clustering in HSV space).
The most common colour in each cluster is then returned. It is
hoped this will give a good balance between reflecting the pokemons
colouring while giving relatively distinct colours.