Adding the Concept of Tasks to SMTK

[johnt]

@dcthomp

@johnt The list above is similar to, but perhaps not as exhaustive as, the list of color-by modes in your slides from this afternoon. Perhaps you could include that list on discourse as a wiki page so we can all edit it and reconcile with that’s above?

I started Candidate RenderView modes for AttributeViews to list some visualization features. Let me know if that isn’t what you are looking for.