Continued Documentation Updates

1. Finished documentation of all Map Generation related methods and
classes.
2. Added a new class GameObjectBase.
3. Added a new class ImpedingFactor that inherits from GameObjectBase.
4. EntityBase now inherits from ImpedingFactor and has been adjusted to
reflect this.
5. GroundObject now inherits from GameObjectBase and has been adjusted
to reflect this.