Start on ECS. Lots of cleanup.
MeshRenderer is now unused, so deleted.
More cleanup.
Mesh class is smaller.
Mesh shader moved to MeshRenderingSystem
SpriteRenderingSystem working.
Text working through SpriteRenderer.
Text renders to RenderTarget2D
Text working quickly now.
Lots of sprite related cleanup.
Text positioning working.
Text coloring and transparency bugs fixed.
Simplifying sprite related things.
Moving MakeSpriteMatrix to the Sprite class.
Textures flipped the right way again.
Fixed glitch with text on multiple lines.
Anchored sprites in top-left again.
Set text background to transparent again.
RenderTarget2D and positioning both working.

I think.
Text works with different size fonts.