improvement: disable color map of the model while plotting residuals

[eqamili]

I tried to plot the F - F_Chaos on a global map and as result I see the residuals displayed as color maps on the satellite tracks + the color map of the model (F_Chaos).

It could be very useful to display only the color maps on the satellite tracks (disabling the color map of the model).

[pacesm]

@eqamili, thanks for the suggestion. I'll check what we can do about it.

[pacesm]

@eqamili, FYI, it is possible to hide the displayed model by setting it completely transparent. Plus, the checkbox at the bottom removes the color bar.