Made Replay class iterable

Makes it so my scala can look like this:

```scala
  def main(args: Array[String]): Unit = {
    val replay = new Replay(args(0))

    for (state <- replay) {
      val player = state.getDotaPlayerByIndex(0)
      val hero   = player.getHero
      if (hero != null) {
        println(hero.getHero+" : "+hero.getCoordinates)
      }
    }
  }
```