This simplifies the rendering code and remove all(!) pointers. There is a number of unresolved issues * Windows build ? * position delta computation: migrating to SFML seems to have modified the frame rate.
Using SDL2_ttf and fmt
* Beginning rewrite * Move all constants to canvas, wire sprite handling code * Make Sprite a struct and reformat * Fix warning Co-authored-by: Corentin Jabot <corentinjabot@gmail.com>