Unit_Genviron (ul_pbar_graphics)

 *  Unit intent:
 *    The module GU functions in this unit provide the following miscellaneous
 *    graphics utilities:
 *  GU__RestoreEnvironment()  Restore previously saved graphic env.
 *  GU__SaveEnvironment()   Save away current graphic environment
 *  GU__SelectScreen()    Select graphics screen
 *    Prototypes for these routines and the associated data types and constants
 *    are contained in the ul_pbar_graphics:gu.h header file.