* GetCanvasPointer() is now a Canvas function pointer. This is a
breaking change, but it should allow any Canvas-derived object
to be fed an arbitrary ARGB surface if the implementer chooses
to take that approach.
* Canvas and Sprite textures are created in a more consistent way.
* The background Canvas now uses the same functions that Sprites
use for texture creation and updates.
* Added a public UpdateTexture() function so that implementers can
manually update sprites if necessary. This should not be used
too often as it can lead to performance issues.
* The SpriteList now initializes Sprites using the stanard Canvas
initialization routines.
* Implemented two moveable "players" in Sample.Sprites.
* Sprites can actually be drawn! Alpha and blending modes are not
supported at the moment.
* Replaced homegrown Vector2 class with the accelerated one from
System.Numerics.
* Added new Sprite initializers to take advantage of the new
ZOrder field. Changed Point data types to Vector2 where
appropriate.
* Began working on a Sprites sample project.
Ian Burgmyer