Rename colorProvider setting to nodeFillColor

[pverscha]

There are currently two different option settings for determining the color of a node: nodeFillColor and colorProvider. The colorProvider should be renamed to nodeFillColor and nodeFillColor should be removed in order to avoid confusing our users.

Note that we should also update the documentation and Observable notebook accordingly.

[bmesuere]

Should we add an alias and mark the old name as deprecated as a first step? Because otherwise this will break for existing users.

[pverscha]

Good point, I'll update it as you suggested :)

[pverscha]

After some more investigating, I found out that all settings related to color behave identically to how they behaved in version 1 of the visualizations, except for one: nodeFillColor.

Setting nodeFillColor to (d) => "#00FF00" results to this in v1.0 of the treeview:

And has no effect in v2.0:

This is due to the fact that no fill is set for the nodes in v2.0, which we should fix. I propose that we do not rename the option and that I fix the nodeFillColor setting. All behaviour will then be identical to v1.0

[pverscha]

Fixed in #68.