CLIPPER 5.2 SCREEN DRIVERS
 _FLPCURSOR() Turns on a flashing cursor.
 DRV_BEGIN()  Sets up the Clipper screen drivers for the graphics screen.
 DRV_CURSOR() Sets attributes for the graphics cursor.
 DRV_END()    Returns the screen to standard Clipper text.
 DRV_FONT()   Changes the font used for the graphics screen drivers.
 DRV_ORIGIN()   Sets the top left of the virtual screen.
 char *flp_drv_paint()   Repaints an area of the screen from C.
 char *flp_drv_scrptr()  Gives access to the flipper text screen from C.