Large Graphical Update

Additions:
-Screen pans in all directions to follow user
-Skyline added at the bottom of the screen
-----(scrolls opposite direction of user)
-Movement of entities adjusted to handle non-flipped y-axis of lwjgl
-X and Y offsets passed to draw-methods of all entities
-Gravity flipped to handle non-flipped y-axis
-Bottom-limit enabled at y=0