Add auxiliary apply[T,U:HTML](fn: T => U) to HTML
Add auxiliary apply[T,U:HTML](fn: T => U) to HTML

This allows to write:

implicit val htmlX = HTML[X, xml.NodeSeq](_.toNodeSeq)

instead of:

implicit val htmlX = HTML[X] { obj =>
    implicitly[HTML[xml.NodeSeq]].stringify(obj.toNodeSeq)
}

nkhuyu/IScala,mattpap/IScala,nkhuyu/IScala,mattpap/IScala