[TD] final fix of compilation after #8141

- in DimensionValidators.h the declarations must not be with TechDrawExport
- add missing precompiled headers

- also fix too long lines (fixed by clang)
- also some re-sorting
- also remove unused headers

src/Mod/TechDraw/Gui/ViewProviderDrawingViewExtension.cpp

@@ -21,23 +21,22 @@
  ***************************************************************************/
 
 #include "PreCompiled.h"
-
 #ifndef _PreComp_
-#include <QMessageBox>
+# include <QMessageBox>
 #endif
 
 #include <App/Document.h>
 #include <App/DocumentObject.h>
 #include <Base/Console.h>
 #include <Base/Tools.h>
-
 #include <Mod/TechDraw/App/DrawPage.h>
 #include <Mod/TechDraw/App/DrawTemplate.h>
 
-#include "ViewProviderDrawingView.h"
 #include "ViewProviderDrawingViewExtension.h"
+#include "ViewProviderDrawingView.h"
 #include "ViewProviderPage.h"
 
+
 using namespace TechDrawGui;
 
 EXTENSION_PROPERTY_SOURCE(TechDrawGui::ViewProviderDrawingViewExtension, Gui::ViewProviderExtension)