Gui: cleanup includes in *PyImp.cpp

Sort includes and implicitely add missing ones. While there
consistently explain where generated files some from.

src/Gui/ViewProviderGeometryObjectPyImp.cpp

@@ -21,19 +21,16 @@
  *                                                                         *
  **************************************************************************/
 
-
 #include <sstream>
 
-
 #include <App/GeoFeature.h>
 #include <App/MaterialPy.h>
 #include <App/PropertyStandard.h>
 
+// generated out of ViewProviderGeometryObject.pyi
 #include "ViewProviderGeometryObjectPy.h"
-
 #include "ViewProviderGeometryObjectPy.cpp"
 
-
 using namespace Gui;
 
 // returns a string which represents the object e.g. when printed in python