* Removed System.Numerics.Vectors dependency. Implemented basic
Vector2<T> type to replace it.
* ScalingQuality can now be changed for each canvas independently,
as well as for the rendering target texture.
* Point type is now based on the new Vector2<T> generic.
* Sprite drawing has been implemented but is still untested.
* The SdlPoint/SdlRect objects in the Point/Rectangle classes
are now exposed to DotSDL for plotting purposes.
* Added some rotation center support (not fully realized).
* Sprites can now be initialized with the clipping rectangle.
* Removed RenderFlip in favor of DotSDL's FlipDirection. The
enums were were effective identical.
* Started working on Sample.Sprites.
* DotSDL's Point and Rectangle classes now use SdlPoint and SdlRect
structs internally to store their data.
* The Sprite class has been fixed, so DotSDL compiles again. Whoops.
* Added a public Rectangle struct.
* Added a constructor for the Point struct to slightly reduce typing fatigue. :)
* Modified the way that Canvas classes are initialized so that
sprite sheets and scrolling backgrounds will be possible to
implement.