Add bridge from Throwable to E for ApplicativeError

Interacting with code that can throw exceptions can be awkward when working with ApplicativeError if E isn't Throwable, because the ApplicativeError#catch* methods don't really have a way to bridge into F unless you know what F is.

You can absolutely make it work, you just can't really leverage the ApplicativeError#catch* helpers, which is a shame because they're really handy, and I think it would be really straightforward to offer alternatives that are more generally applicable.

I propose adding parallel methods which would allow adapting a Throwable to an E. For example, ApplicativeError#catchNonFatalAs could look like this:

  /**
   * Often E can be created from Throwable. Here we try to call pure or 
   * catch, adapt into E, and raise.
   *
   * Exceptions that cannot be adapted to E will be propagated 
   */
  def catchNonFatalAs[A](adaptIfPossible: Throwable => Option[E])(a: => A): F[A] =
    try pure(a)
    catch {
      case NonFatal(e) => adaptIfPossible(e).map(raise(_)).getOrElse(throw e)
    }

Similar methods could be created for ApplicativeError#catchNonFatalEval and ApplicativeError#catchOnly.

Start by locating the ApplicativeError definition and its existing catch* methods. Compare the proposed catchNonFatalAs, catchNonFatalEval, and catchOnly variants, then add coverage showing Throwable adaptation into E and propagation when adaptation fails; done means the parallel helpers are available with consistent behavior.