Map dungeon 1

[Diarandor]

Most part of the mapping will be done by @zeldoretro_twitter, as discussed on gitter.
We will use a Forest Theme, as in the original game: green walls.

Things TODO (this list will be updated from time to time):

• Map plain walls and grounds, just the basic structure of the dungeon.
• Add enemies and test them, and the dungeon difficulty. Change the number and location if necessary. This dungeon should be slightly challenging but not too hard.
  Enemies that we could use: goblins of all types, green slimes, chameleons.
• Add decoration tiles: first to tileset, later to dungeon walls.
• Add miniboss: ???
• Add boss: ???
• Add remaining code for keys, and other savegame variables.

List for other missing things (details, entities, missing tiles/sprites, etc):

• If the dungeon is too short, we could add a new extra floor and change the miniboss location.
• ???