1. game.AddObject added {empty}
2. Merged RandomFishGenerator.java and MainGame.java
3. Deleted RandomFishGenerator.java
4. Renamed addFish() method to addObject() method in MainGame.java
5. Changed addObject() method structure to include switches for other types of objects.
1. Move All addObject() related methods to AddObject.java
2. MainGame.java code cleanup.