GraphDefaults procedure

  DECLARATION:  GraphDefaults

      PURPOSE:  Resets the graphics settings

         UNIT:  Graph

      REMARKS:  This homes the current pointer (CP) and resets the graphics
                system to the default values for:

                - ViewPort
                - Palette
                - Draw and Background colors
                - Line Style and Line Pattern
                - Fill Style, Fill Color, and Fill Pattern
                - Active Font, Text Style, Text Justification, User Char Size

 RESTRICTIONS:  Must first be in graphics mode.