Working instructions for 2.10.x

A build for 2.10.4 is not available - but it should not be needed.
Bumped Scala version to 2.10.4.
Add `zipWithKeys` to turn an HList into a record

This is useful when you want to take an input HList, perform
transformations on the values, and then return the results as a record with the
original keys. This can be more convenient than tracking the fields the
whole way through the transformation.
Add zipWithKeys to Coproduct
Consistency: Lens -> lens.
Split off Zipper ops and syntax.
Merge remote-tracking branch 'github/pr/89'
Merge remote-tracking branch 'github/pr/87'