Forwarded binding improvements

[ddworak]

Follow-up from #282

val p = Property(2)
val s = Property(3)

div(
  produceWithNested(p.transform(_ + 1)) { case (v, nested) =>
    div(
      nested(produce(s) { v2 =>
        println((v, v2))
        div().render
      })
    ).render
  }
).render

CallbackSequencer().sequence {
  p.set(20)
  s.set(30)
}

CallbackSequencer().sequence {
  s.set(300)
  p.set(200)
}

prints:

(3,3)
(3,30) // ???
(21,30)
(21,300) // ???
(201,300)

In the example, the (21,300) case is not avoidable, but the (3, 30) should be (as we've seen in previous changes). The callbacks are sequenced correctly there according to our current logic - the listeners are on a derived/forwarded property, therefore its callbacks are queued and executed at the end.
We can consider pinning callbacks for derived properties to origin, but I'm not sure it's possible in all cases yet.