Parse the tiled map and generate Tile objects
Avoid circular map when accessing tiles matrix which negative values
Use DungeonLevelMap to handle TiledMap abstraction

TODO

* Unload Tiles dynamically when they are not needed

Generating a definite range of Tile objects in a parser could lead to
performance/memory issues for large maps
Handle walkable Tiles for Characters
DungeonLevelMap discards Tiles that don't have characters on them
Remove useless abstraction
Simplify ternary condition
Merge pull request #50 from rafaelgonzalez/level-tiles-abstraction

Level tiles abstraction