Create an Enumeratee that recovers an iteratee in Error state.

This enumeratee will ignore the input that caused the iteratee's error state and use the previous state of the iteratee to handle the next input.
```scala
Enumerator(0, 2, 4) &> Enumeratee.recover { error =>
   Logger.error("oops failure occured", error)
} &> Enumeratee.map { i =>
   8 / i
} |>>> Iteratee.getChunks // => List(4, 2)
```