GUI: Allow "interactive" input fields

[pfebrer]

It may be interesting to allow the user to toggle the interactivity of an input field, in the sense that when they change the value of that input field the plot updates automatically instead of needing to click "update settings".

This can be dangerous for heavy plots and/or settings that when updated trigger long calculations, but it might be very helpful for more dinamic cases, as it makes the exploring experience better.