NICTA/scoobi — pull request #219 by espringe (2013-03-18 17:19:14+00:00)
Title: Relax the DList conversion constraints

This allows the .toSequenceFile and .toAvroFile methods to be visible
and discoverable without yet having the implicits written

Last time I was missing one of the (T <:< (K,V)) constraints, so it was getting a manifest for `Nothing` rather than the proper K and Vs