lumber mill is added

- I added the lumbermill.js and the images for it

-The lumber mill is animated, again use the core to edit its position if
needed. Also some of the parts are added to game.stage and others are
added to the core, all of the parts are relative to the core

- if you need to delete the mill, call the destroy(); function that it
has because it will stop all the tweens and delete each sprite whether
it was added to the core or game stage