Changed the starting values of the tank in Player
Added a lastPos variable to MovableEntity

The variable is used for handling collision, at the moment only in
AbstractTank.
Added additional players for testing purposes
AbstractObstacle now has a shape when created
Changed protected variables to private and added damage

The damage part needs to be discussed.
Set the health of DefaultTank to 100
The shape is now set in AbstractObstacle to prevent duplicate code
Changed the turnSpeed and also fixed so that collision works a lot better

The collision should now work while turning next to a wall while
standing still, preventing the tank from getting stuck. The tank
shouldn't be able to drive outside the map anymore.
Set the damage of DefaultProjectile to 5
Now using getters instead of the variable names since they are private now