added a side channel that reports the sum of the weight of the neighbors for the knn recommender algorithms (user-user and item-item)
fixed stupid typo
Merge https://github.com/grouplens/lenskit
changes made to allow measuring diversity and popularity of topN recommendations.
added a not n entropy metric
cleaned up diversity and entropy metrics
cleaned up work-in-progress changes to lenskit topN recommenders for merging
Merge https://github.com/grouplens/lenskit
fixed typo in documentation
fixed a null that was causing NPE durring code evaulation.
fixed a few small issues that were found in code review
Merge pull request #516 from kluver/master

Make TopNMetrics a little easier to build by writing an inheritable builder.