This corrects which end of the slot Extend Slot Start/End are applied; error with Extend lengths between 0 and 1 and direction of extention on arc slots ( neg. is shorten ).
Some renaming to make code more readable and self documenting.
Many Path object forward its editing operation to the job object. It is
possible that some editing option change may lead to removing of the
editing object (e.g. changing stock type) causing crash. It is possible
to just open the task panel without setting any editing object by
returning False in ViewProvider.setEdit()
Error was thrown if FreeCADGui.Selection list had more than one item. Solution is to clear selection before adding selection from import operation. I also removed the `for` loop since the selection should be singular.
The class variable name was not corrected with previously committed changes.
The correct cutting edge variable name is located in the __init__() constructor method.