Fixed signatures for on_save_preset and on_value_change function objects.
Fixed signatures for on_save_preset and on_value_change function objects.

alexrj/Slic3r,alexrj/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,curieos/Slic3r,alexrj/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,lordofhyphens/Slic3r,lordofhyphens/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,alexrj/Slic3r,curieos/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,pieis2pi/Slic3r,lordofhyphens/Slic3r,pieis2pi/Slic3r,alexrj/Slic3r