big changes added. restruct src.
	modified:   2048.go
	new file:   box/box.go
	new file:   box/merge.go
	new file:   box/print.go
	renamed:    other/BoxTransform.go -> box/transform.go
	new file:   box/win.go
	new file:   demo/demo.go
	deleted:    other/TestMain.go