[Gimp-gui] Make the selected tool default to the Color Picker instead of the last tool used

[Elle Stone <ellestone ninedegreesbelow com>]

This is a change to the GIMP user interface that I've wanted for a long 
time. It probably would only benefit people who use the Color Picker a lot.

When you use a tool, say Curves, and the operation completes, and then 
you click on the canvas again, Curves pops up again, unless you remember 
to pick a different tool.

Almost never do I actually want to use same tool that I just used, 
immediately again.

Almost always the tool I really want to use next is the Color Picker.

It would be nice to have the option in Preferences, maybe under the Tool 
Options,  to set a "default tool", such that regardless of what the last 
tool used happened to be, upon completing the algorithm, the selected 
tool would reset itself to the user's chosen default tool.

This would eliminate the problem of having to continually reselect the 
Color Picker (if that's the tool the user chose as the default tool), 
and dismiss unwanted dialogs that pop up, and wait for unintended 
editing operations to complete before hitting the "undo" button.

Maybe there's already a way to do this in Preferences, and I just 
haven't found it?

Elle