Change CMakeLists.txt to add 2d_game project, and added irrKlang to LIBS.

Added irrKlang.dll and ikpMP2.dll to dlls folder.  Added irrKlang as a
sub-folder under includes.  Added irrKlang.lib to lib folder.  At this point
running cmake gave an error it couldn't find source files under 2d_game.
Moved 2d_game source up one folder level, then cmake found the files.

src/7.in_practice/3.2d_game/0.full_source/game_level.h

@@ -1,41 +0,0 @@
-/*******************************************************************
-** This code is part of Breakout.
-**
-** Breakout is free software: you can redistribute it and/or modify
-** it under the terms of the CC BY 4.0 license as published by
-** Creative Commons, either version 4 of the License, or (at your
-** option) any later version.
-******************************************************************/
-#ifndef GAMELEVEL_H
-#define GAMELEVEL_H
-#include <vector>
-
-#include <glad/glad.h>
-#include <glm/glm.hpp>
-
-#include "game_object.h"
-#include "sprite_renderer.h"
-#include "resource_manager.h"
-
-
-/// GameLevel holds all Tiles as part of a Breakout level and 
-/// hosts functionality to Load/render levels from the harddisk.
-class GameLevel
-{
-public:
-    // level state
-    std::vector<GameObject> Bricks;
-    // constructor
-    GameLevel() { }
-    // loads level from file
-    void Load(const char *file, unsigned int levelWidth, unsigned int levelHeight);
-    // render level
-    void Draw(SpriteRenderer &renderer);
-    // check if the level is completed (all non-solid tiles are destroyed)
-    bool IsCompleted();
-private:
-    // initialize level from tile data
-    void init(std::vector<std::vector<unsigned int>> tileData, unsigned int levelWidth, unsigned int levelHeight);
-};
-
-#endif