W00t Maps

Created a new class called Map. Map has an array of DisplayObjects
(Tiles) that it tracks in even sized squares and updates. The addition
required changing DisplayObject to give it a Draw method. Previously,
the Display was responsible for generating the destination rectangle and
placing the DisplayObject on the screen.

Now that the DisplayObject is in control of the draw, Map can iterate
through all of its DisplayObjects and draw them to the screen. This
includes both DisplayObjects and AnimatedSprites (polymorphism).

Now the AnimatedSprites need to be updated to have an image update
sequence. Using an atlas of background images seems like a good idea. By
indexing the type of tile for the background, we can store the
background as a numeric array and read in its corresponding texture when
loading the map (use it with no animation, but grabbing the picture like
a cookie cutter). Also, this will allow minor animations in the
background.