Create object properties module

Objects/Properties.hs
This module contains type classes that types have to obey to qualify as
a game object.
Implement liftState function
Implement test for makeByOrdering

Utils/Tree.hs
We implemented a test that checks if a tree generated by
`makeByOrdering' is balanced.
Improve collision detection

Objects/Space.hs
- contains is no longer a function of InSpace objects but of Areal
  objects
- implement functions to check if a point is in a line or a section of a
  line
- reimplement most of the collision detection

Background.hs, Camera.hs, Enemy.hs, Projectile.hs, Player.hs
- adapt to changes is Space.hs

Objects/SpaceTree.hs
- rewrite almost everything
- write a lot of tests for almost all the functions

Objects/SpaceTree/Interval.hs
- contains the interval stuff for the collision detection