Updated wxPallete information.

Added GetColourCount() implementation to Carbon (I wonder
    why it doesnt just use the generic implementation).


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41405 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/image.tex

@@ -579,9 +579,9 @@ used as a mask colour. Returns {\tt true} if the image currently has a mask.
 \constfunc{const wxPalette\&}{GetPalette}{\void}
 
 Returns the palette associated with the image. Currently the palette is only
-used when converting to wxBitmap under Windows.
-
-Eventually wxImage handlers will set the palette if one exists in the image file.
+used when converting to wxBitmap under Windows. Some of the wxImage handlers
+have been modified to set the palette if one exists in the image file (usually
+256 or less colour images in GIF or PNG format).
 
 
 \membersection{wxImage::GetRed}\label{wximagegetred}