Start work on a generic actor class, and have Enemy extend it

Actors are intended to do the following
- move within a tilemap
- react to other actors moving within a view range
- react to collision
- be capable of attacking one another
- move in multiple directions
Throw in a holder class for Bullet logic
Start work on World manager

Worlds do the following
- Manage all actors in it
- Update the views of awareness of enemies
- Handle initialization of new waves of enemies
BrickRenderer is not used, get rid of it