Map update overhaul - Githubissues

This tiny tool could be a lot more powerful. Some features I'm thinking about:

Up- and Downgrading maps
Two modes: embed tilesets or update tile indices
Compatibility mode: embed tilesets and use 0.6 tile-layer format, so bother versions can use the map
Support DDNet map extensions (#15)
Maybe: use some more extensible format as output (UUID based)
Maybe: web version for easy usage

axblk / teeworlds