XYGraph__Initialize (ul_pbar_graphics)

 *  Synopsis:
 *    #include <ul_pbar_graphics:xygraph.h>
 *
 *    TXYGraph__Result XYGraph__Initialize( long int whichScreen,
 *					    const char *windowTitle )
 *
 *  Function intent:
 *    XYGraph__Initialize() initializes the graphic display device and
 *    establishes default values which provide for the basic X-Y graph display.
 *    XYGraph__Initialize() must be called before any other XYGraph functions.
 *  Function parameters:
 *    long int	whichScreen	desired display screen (GXPA_1 or GXPA_2)
 *    char	*windowTitle	pointer to display device window title string
 *  Function return value:
 *    CBS_OK		success
 *    CBS_MEMFAIL	on memory allocation failure
 *    else 		wn_xxx() function error status