+size is smaller than the item's GetBestSize. When a window is added
+to a sizer it's initial size, if any, is set as the window's minimal
+size using SetSizeHints if there isn't already a minimal size.
+
+Added some convenience methods to wx.Bitmap: SetSize, GetSize, and
+wx.EmptyBitmap can be called with a wx.Size (or a 2-element sequence)
+object too. Similar changes were done for wx.Image as well.
+
+