Parallel Coords plot causes fatal error

[martinfalk]

In some instances the parallel coordinate plot causes fatal errors when using a categorical column for coloring. This happens when there are more categories than colors supported by the colormap.

If colorbrewer does not support the number of colors, the PCP should at least deal with problem gracefully and not just let the exception pass to the main event loop!

[martinfalk]

We should consider recycling colors for additional categories

[PetiteViking]

A simple solution is to ask colorbrewer if the number of categories is supported for the selected family and of not, generate a set grayscale colors.

It's not pretty but it's failsafe.