NAME   
        InitVPort - Initialize viewport structure.

   SYNOPSIS
        InitVPort( vp )
                   a0

        void InitViewPort( struct viewport * );

   FUNCTION
        Initialize viewport structure to default values.

   INPUTS
        vp - pointer to a viewport structure

   RESULT
        viewport structure set to all 0's. (1.0,1.1)
       New field added SpritePriorities, initialized to 0x24 (1.2)

   BUGS

   SEE ALSO
        makevport() graphics/view.h