Use some new features: \<10> macro args, SECTION UNION, SIZEOF/STARTOF, and CHARLEN/CHARSUB
- fail for rgbds < 0.4.0 - `rst <Label>` - `ds <count>, <byte>` - `shift <N>` - ASCII "\r" - Sorted .sym file
We used to have a mixture of TileMap and and Tilemap, as well as the similar AttrMap. Standardize on one.