Added the CURSOR_KEEP and CURSOR_OWNED options for the FXCursor class, similar to theIMAGE_KEEP and IMAGE_OWNED options for the FXImage class.

The new isColor() member function for the FXCursor class returns TRUE if the color of any of the non-transparent pixels in the cursor isn't black or white.

The savePixels() and loadPixels() member functions now return FXbool (instead of void).