Simpler and consistent color-by mode and default.
- Use the new ParaView plugin macro
add_paraview_toolbar
instead ofadd_paraview_action_group
. - Make the default color-by mode for SMTK models "Entity", not "Field."
- Disable the "Active Variable Controls" toolbar when ParaView's active representation is an SMTK model (unless the model is being colored by field values).