Gave the Tile-Enum its own file (which will then include all tile types)
Sky-Tiles are used instead of just empty blue space.
In DrawUtil is a new function that scans the folders of all tile-types and creates a map. With getRandomImage(TileEnum type) you get a random image of the tile-type.
Merge branch 'master' of https://github.com/Laranto/airship-crew