Cleaned up included

-Removed as many headers as possible from header fiels
-Added needed header to .cpp files
-Added forward declarations
-Moved Init() from MenuManager.h to MenuManager.cpp to enable removing
including of Renderer.h in MenuManager.h
Code cleanup in Renderer

-Removed empty lines
-Fixed typs
-Made all getters const
-Moved clean up code down and added a header
Code cleanup in GameManager and PhysicsManager

-Removed empty lines
-Moved single line recieve functions into switch and removed functions
GamePice objects are now rendered in RenderHelpers

-Moved SDL_Texture* with its setters and getters to GamePiece fro
BonusBox. This means each object in the game ( objects of classes
	derived from GamePiece ) will have a pointer to its on texture.
-Added code for setting the texture when the object is added to
Renderer. ( AddBall(), AddBullet(), AddPaddle(), AddBonusBox(),
	AddTile() )
-Implemented RenderGamePiece() in RenderHelpers. The methods renders
objects like BonusBoxes were rendered; by getting the rect and texture
from the GamePiece object itself.
-Changed Renderer to use the above method for all GamePiece objects