Replace use of Matrix.inverse() with inverseGauss()

Because of possible scaling involved.

src/Gui/ViewProviderLink.cpp

@@ -2401,7 +2401,7 @@ bool ViewProviderLink::initDraggingPlacement() {
 
     dragCtx->preTransform = doc->getEditingTransform();
     auto plaMat = pla.toMatrix();
-    plaMat.inverse();
+    plaMat.inverseGauss();
     dragCtx->preTransform *= plaMat;
 
     dragCtx->bbox = linkView->getBoundBox();
@@ -2409,7 +2409,7 @@ bool ViewProviderLink::initDraggingPlacement() {
             dragCtx->bbox.GetCenter(),Base::Rotation());
     dragCtx->initialPlacement = pla * offset;
     dragCtx->mat = offset.toMatrix();
-    dragCtx->mat.inverse();
+    dragCtx->mat.inverseGauss();
     return true;
 }
 

src/Mod/PartDesign/App/ShapeBinder.cpp

@@ -361,14 +361,14 @@ void SubShapeBinder::update() {
                         first = false;
                     } else {
                         // The remaining support will cancel the Placement
-                        mat.inverse();
+                        mat.inverseGauss();
                         res.first->second = mat;
                     }
                 }else{
                     // For newer SubShapeBinder, the Placement property is free
                     // to use by the user to add additional offset to the
                     // binding object
-                    mat.inverse();
+                    mat.inverseGauss();
                     res.first->second = Placement.getValue().toMatrix()*mat;
                 }
             }