- Added FlatRenderProgram to render 2D graphics - Can be used as-is - Supports rectangular coordinate-aligned nested masks - Added AssembledFlatLayer to cache 2D graphics - Use RenderTarget for add elements during reassembly - ShapeRenderProgram now allows null textures (defaults to white BG) - Sprite now deduces size based on primitive's content size - unless given size explicitly - ShapeRenderHelper.*WorldTransform methods renamed to .*Transform