Gui: Optimize includes to reduce compile time

src/Mod/Drawing/Gui/DrawingView.cpp

@@ -54,9 +54,11 @@
 #endif
 
 #include "DrawingView.h"
+#include <Base/Parameter.h>
 #include <Base/Stream.h>
 #include <Base/gzstream.h>
 #include <Base/PyObjectBase.h>
+#include <App/Application.h>
 #include <App/Document.h>
 #include <Gui/Document.h>
 #include <Gui/ViewProvider.h>

src/Mod/Image/Gui/ImageView.cpp

@@ -30,6 +30,8 @@
 #include "ImageView.h"
 #include "../App/ImageBase.h"
 #include "XpmImages.h"
+#include <Base/Parameter.h>
+#include <App/Application.h>
 
 using namespace ImageGui;
 

src/Mod/Part/Gui/TaskCheckGeometry.h

@@ -39,6 +39,7 @@ class SoSeparator;
 class SoSwitch;
 class QCheckBox;
 class QTextEdit;
+class QTreeView;
 
 namespace PartGui {
 

src/Mod/TechDraw/Gui/QGIViewPart.h

@@ -25,6 +25,7 @@
 
 #include <QObject>
 #include <QPainter>
+#include <QStyleOptionGraphicsItem>
 
 #include <Mod/TechDraw/App/Geometry.h>
 #include "QGIView.h"