169B Week3 NULLPTR

changes: 

1.ESC to pause, load ,save and see the game control UI

2. start page to choose level or start new game 

3.Helpful text boxes will appear for certain interactable objects

4.Adjusted chatacter speed (gliding fall, movement speed, etc.) 

5.-Added mushrooms and readjusted ground sizes to new character speeds

6. run as default  and shift to slow down