Added a move method to Player.
Made the tiles array of a Chunk private, added a get method for getting tiles.
Added a field indicating the tile index of the bottom-right tile in the chunk, relative to the whole world, a get method to retrieve it, and a constructor argument to set it.
Altered the constructor invocations for Chunk objects to include the new parameter added in the previous commit.
Added code to display the world in the window.
Added code to take arrow-key inputs and update the player position.
Added a function to convert from a tile index to window co-ordinates.

Currently incorrectly only displays one chunk.