|SOURCE|
[Common::BaseGameEntity]
* Added a member function, GetType, which can be used to retrieve any relevant
  information from the derived class without knowing the derived type
[Common::BaseGameEntityRenderable2D]
* GetType returns LD_RENDERABLE_2D
* Constructor and destructor handle nullifying objects and deleting them,
  respectively
[Common::DataTypes]
* Added a helper function, ldSafeDelete, to make sure the pointer it's deleting
  exists and sets it to LD_NULL afterward
[Common::Game]
* Added an instance of GameEntityManager which will handle the life of game
  events
[Common::GameEntityManager]
* This class handles the life cycle of game entities, which are able to be
  renderable and updatable