add SetRGB overload

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75673 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/image.h

@@ -1670,6 +1670,12 @@ public:
     */
     void SetPalette(const wxPalette& palette);
 
+    /**
+       Set the color of the pixel at the given x and y coordinate.
+    */
+    
+    void SetRGB( int x, int y, unsigned char r, unsigned char g, unsigned char b );
+
     /**
         Sets the colour of the pixels within the given rectangle.