First attempt at combiner for seq2sparse outputted vectors
A few fixes and some cleanup.  Compiles.
Fixed second loop in Comibiner, cleanup, comments
Remove unused imoport, add some comments
comments, javadoc, liscense
change blockB to blockA.like and setter to setQuick
change trainNB to accept a DrmLike[Int]
comments
Change extractLabelsAndAggregateObservations to take a DrmLike[K] rather than [String]
Cleanup, comments