Fem: [skip ci] Fix several clazy issues:

* Maybe you meant to call base method instead [-Wclazy-skipped-base-method]
* Using copy-ctor but class SbMatrix has a trivial copy-ctor but non trivial assign operator [-Wclazy-rule-of-two-soft]
* Missing emit keyword on signal call FemGui::PointMarker::PointsChanged [-Wclazy-incorrect-emit]

src/Mod/Fem/Gui/ViewProviderFemPostFunction.cpp

@@ -442,7 +442,7 @@ void ViewProviderFemPostPlaneFunction::onChanged(const App::Property* prop)
             // get current matrix
             SbVec3f t, s;
             SbRotation r, so;
-            SbMatrix matrix = getManipulator()->getDragger()->getMotionMatrix();
+            SbMatrix matrix = getManipulator()->getDragger()->getMotionMatrix(); // clazy:exclude=rule-of-two-soft
             matrix.getTransform(t, r, s, so);
 
             float scale = static_cast<float>(Scale.getValue());