Add Character slash animation mapping
Characters have health and armor
Add effects Array to Tiles, apply them when stacked
Implement UnarmedAttack and apply Damage effect
Characters can use Skills
Bind UnarmedAttack skill to E key
Character movement is now split in four skills
Move DungeonLevelActor#adjacent_tile_from_direction to Tile#adjacent_tile
skills.rb should define Skills module
Merge pull request #56 from rafaelgonzalez/skills-models

[WIP] Skills-related models