Shape's outline color from a table column

[marcovarrone]

Currently, the color of a set of shapes can be set according to a column in the table, but for the outline, it's only possible to specify a single color common to all shapes.

I would like to propose the possibility to select different outline colors for different shapes.

My use case is that I automatically generate annotated regions around certain groups of cells and I want to display only the outline because these regions can contain heterogeneous cells (colored + grey) that I still want to be able to show, as in the example in the following image.

If you think it's a good idea I can attempt a PR :)