lots changes:

- renamed scene files
- fixed options back using scene.Prev
- fixed initial zooming (finally)
- fixed reset zoom (key r)
- fixed initial size, now works with state loading as well

scene.go

@@ -13,6 +13,7 @@ type SceneName int
 type Scene interface {
 	SetNext(SceneName)
 	GetNext() SceneName
+	SetPrevious(SceneName)
 	ResetNext()
 	Update() error
 	Draw(screen *ebiten.Image)