Add `assertEquals(meta, AtlasMeta.fromJSON(AtlasMeta.toJSON(meta)))` test.
Revise AtlasMeta.fromJSON().
Explore an AtlasMetaParser revive-based API instead parsing as JSON as a second pass.
Add FilmID argument support to atlas-pack executable.
Add a more thorough demo. For example, a very small game showcasing a few things: different collisioning (including Aseprite GUI screenshots of slices), tiling, different animations, parsing and image loading, a mini sprite / entity system.