rewrite binders using shapeless

[bblfish]

@milessabin's at the Dublin Scala user's group shows how to remove the boilerplate from case class serialisers and deserialisers, based entirely on compile time type inferencing. Also what he shows without mentioning it is what appears in CategoryTheory as the notion that products and sums are opposites. ( A sum in one category will be a product in the opposite category - the category where all arrows are reversed ) Products are mapped to class fields, and sums to subclassing... ) See the video https://www.youtube.com/watch?v=LaOiBdrM8uo

This could make the binders package much more useable.

[bblfish]

If you're wondering in the talk about how the unification of products and sums will go in Shapeless 3, Miles Sabin wrote: "If you want a taste of how this will play out in shapeless 3 you should take a look here: https://github.com/.../src/main/scala/shapeless/smc.scala
As you can see there we can abstract over products and coproducts in a way which means that we can share all the operations between the two.
It also demonstrates that we don't need to commit to any particular concrete carrier type (ie. the current HList and Coproduct types), we can just as easily use nested pairs and Either (or anything else structurally similar)."