- Created the class "Action" that should be used for entities, fields
and items to interact with each other.
- Added the Action "Move" and "DirectedMove" to remodel the movement of
the Entities
- Added a routine in the class "Map" to  associate Actions with the
current active map. This is realized as a static attribute in the class
"Action"
- TODO: Remodel the movement-behavior of the entities with the Action
class