We need a GUI for the lazy brush functionality. Basically, the filling should be done by a special kind of a mask. This mask can work in two modes: "mask mode" and "split layers mode". We can implement either both modes or just one of them. It should be decided.
If using split layer mode, the folloowing questions should be answered:
* what naming scheme should be followed by the automatically created layers?
* should they be grouped and, if yes, what naming convention should it be?
* what composite op should be used for the filling layers? Should it be configurable? What about opacity?
Here are my very rough mockups/ideas of how it can be implemanted: