Add Monocle support to transformers

Snippet:

``` scala
  implicit val transformRT =
    RT.*.transformer
      .mapR[Ref](r => RT.Ref(r.tester.component zoomL State.rt, r.svr))
      .pmapO[Obs](_.rt)
      .mapS(TestState.project.get)((a, b) => TestState.project.set(b)(a))
      // ↑ TODO Add Monocle support
```
