Refactored Enemies w/ Decorator

Hey @walsh06, @SheepishMonster,
Implemented the Decorator. 
Hopefully I didn't mess up any of your things @walsh06, We may need to be careful when merging our currently open PRs.

Any thoughts/questions?
Looked at it again. I think it was because we were going to use Enemy as an Abstract class, then Basic Enemy was the concrete. BUT I just got rid of BasicEnemy and made Enemy concrete. Tested. All works. Thoughts?