Merge pull request #4 from arcym/master

Established some classes for loading the world.
Entity super class in effect
began listing fields for collision, attributes, movement
added getters and setter for important variables
collision methods added to the entity abstract class
added Enemy class as a subclass of Entity
added a sample enemy class "Thug"
added a populateEnemies method to TiledWorld
Merge pull request #5 from jshiraef/master

Entity and enemies
Refactored attributes up to the entity superclass.
Established an enum for orthogonal direction.
Tried to get the collision to work.
Cleaned up the main loop of the game.