Move list utility function to Utils/List.hs
Move Tree stuff to Utils.Tree module
Instance Projectile and Enemy as Collidable
Implement a labeled tree

/Utils/LabeledTree.hs
* We implemented a procedure to label a tree
* impelemented procedure to find a label item in a tree

/Utils.hs
* changed name of StateMonad to State (the old name was kind of dumb)

/Utils/Tree.hs
* export contructors for Tree also

/Enemy.hs
/Eventlistner.hs
/Objects.hs
/Player.hs
/Projectile.hs
/World.hs
* adjust code to changes with the state monad (StateMonad -> State)