[TD]clazy warnings and duplicate setter/getter

- clazy warning re missing Q_OBJECT

- include TechDrawGlobal.h in headers

- resolve duplicate setter/getters

src/Mod/TechDraw/Gui/DrawGuiUtil.cpp

@@ -129,7 +129,7 @@ TechDraw::DrawPage* DrawGuiUtil::findPage(Gui::Command* cmd)
             MDIViewPage* mvp = dynamic_cast<MDIViewPage*>(mv);
             if (mvp) {
                 QString windowTitle = mvp->windowTitle();
-                QGSPage* qp = mvp->getViewProviderPage()->getGraphicsScene();
+                QGSPage* qp = mvp->getViewProviderPage()->getQGSPage();
                 page = qp->getDrawPage();
             }
             else {