Added wxDC:DrawPolygone

Corrected wxBitmap::SetLabel
  Added wxASSERT here and there
  wxDropSource:DoDrop() now returns Cancel when supposed to


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@476 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/control.cpp

@@ -47,6 +47,7 @@ void wxControl::SetLabel( const wxString &label )
 #endif
     }
 
+    m_label = "";
     m_label << *pc;
   }
 };