Enabling the use of masks for wxGTK in some of the demos

wxWindow.GetHandle returns the X-Window instead of the GtkWidget
pointer so the X-Window can be given to other Python modules such as
VTK.

wxPython.lib.vtk updated to get the window handle at widget creation
instead of in the constructor.

other updates


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@5147 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

utils/wxPython/demo/wxButton.py

@@ -18,9 +18,8 @@ class TestPanel(wxPanel):
         EVT_BUTTON(self, 20, self.OnClick)
 
         bmp = wxBitmap('bitmaps/test2.bmp', wxBITMAP_TYPE_BMP)
-        if wxPlatform == '__WXMSW__':
-            mask = wxMaskColour(bmp, wxBLUE)
-            bmp.SetMask(mask)
+        mask = wxMaskColour(bmp, wxBLUE)
+        bmp.SetMask(mask)
         wxBitmapButton(self, 30, bmp, wxPoint(140, 20),
                        wxSize(bmp.GetWidth()+10, bmp.GetHeight()+10))
         EVT_BUTTON(self, 30, self.OnClick)