Added a Entity Component System for Game Entities

|SOURCE|
[Common/GameEntity]
* Using 32-bit unsigned integers (which will probably need to be expanded to
  wider bit sizes later) to hold the components an entity supports
[Common/GameEntityComponent]
* The game entity component is meant to be as light as possible, only
  containing data and an ID to refer to it
[Common/GameEntityManager]
* A structure of arrays is used to hold entity masks and associated data
* Debugging features have been added, mainly the ability to print out the list
  of components an entity has
* Components can be added or removed from entities via AddComponent,
  RemoveComponent, and SetComponents, the latter overrides the previous
  components set
* Game systems can be added via AddSystem
* The class is currently implemented as a singleton
* Process will call the systems registered
[Common/GameEntitySystem]
* Game entity systems act on game entity component data, this is a base class
  intended to be overridden
[Common/GameplayGameState]
* All previously defined game entity related instances have been removed and/or
  replaced with the new ECS type (though, funcionality is severely lacking)
* ActiveActor is not useful anymore, it will be removed
[Common/Player]
* Commented-out the Player class, as it will be replaced with the ECS type
[Common/PositionComponent]
* Inherits from the GameEntityComponent class to provide positional data for
  the entity it is associated with
[Common/Game]
* Temporarily removed the grab keyboard/mouse and repositioning of the mouse
  for debugging
[Common/GameEntity]
* Removed the definition of the previous GameEntity class