Fix game initialization bugs.

[KoolTheba]

Behaviour Expected

expectations

• Scene should be rendered without enemies or player
• No Errors should be shown in the console

Current Bugs

• ReferenceError: allEnemies is not defined
• ReferenceError: player is not defined
• Uncaught TypeError: player.update is not a function
• Uncaught TypeError: player.render is not a function

[KoolTheba]

Please @hbkwong can you review this PR? I've just tried to solve the initialization issue in the game in order to help others students too ;-)

[himanshu-pareek]

I think, the objective of not providing Player and Player prototypes functions is that everyone should learn how to declare objects and methods by himself/herself from scratch.