This section describes how to set up the vsprite structure so that it
represents a true VSprite.  True VSprites are managed by the GELs system
which converts them to Simple Sprites and displays them.  (Later sections
describe how a VSprite structure can be set up for Bobs and AnimComps.)

Before the system is told of a VSprite's existence, space for the vsprite
data structure must be allocated and initialized to correctly represent a
VSprite.  Since the system does no validity checking on the VSprite
structure, the result of using a bogus structure is usually a fireworks
display, followed by a system failure.

The system software provides a way to detect collisions between VSprites
and other on-screen objects.  There is also a method of extending the
vsprite structure to incorporate user defined variables.  these subjects
are applicable to all GELs and are explained later in the section on
"collisions and gel structure extensions".

 specification of vsprite structure 
 reserved vsprite members 
 using vsprite flags 
 vsprite position 
 vsprite image size 
 vsprites and collision detection 
 vsprite image data 
 specifying the colors of a vsprite 
 adding and removing vsprites 
 changing vsprites 
 getting the vsprite list in order 
 displaying the vsprites