Pawn enemy and enemy spawning

* Added in a crude way of how we are spawning enemies
* Enemies now spawn and shoot projectiles. They spawn every certain amount of seconds
* Started a little bit work on difficulty as levels progress (not implemented yet)
* Did pawn enemy class
* Did Enemy projectile class
* Did a lot of work on GameManager, EnemyManager, and Level classes
* Check out the changes in my scene in the Orlando folder

@ckhamash