Added mouse wheel support for MSW. It generates a wxMouseEvent with a

type of wxEVT_MOUSEWHEEL.

wxMouseEvent has new members and accessors to transport mouse wheel
rotation data.  New members and accessors are documented.

wxGenericScrolledWindow modified to turn mouse wheel events into
scroll actions.

Added wxUSE_MOUSEWHEEL to setup0.h to allow disabling the platform
specific parts.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@9990 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/scrolwin.h

@@ -126,6 +126,7 @@ public:
     void OnSize(wxSizeEvent& event);
     void OnPaint(wxPaintEvent& event);
     void OnChar(wxKeyEvent& event);
+    void OnMouseWheel(wxMouseEvent& event);
 
     // Calculate scroll increment
     virtual int CalcScrollInc(wxScrollWinEvent& event);
@@ -144,6 +145,7 @@ protected:
     int                   m_yScrollLinesPerPage;
     double                m_scaleX;
     double                m_scaleY;
+    int                   m_wheelRotation;
 
 private:
     DECLARE_EVENT_TABLE()