Add passthroughs for Slic3r::ConfigBase::has and diff
Add passthroughs for Slic3r::ConfigBase::has and diff

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