comparator bugfix +  new normalized error measure + dummyContinuous

RankScoreComparator was buggy, failing to take advantage of fractional score differences for ranking.

added new error measure based on conversation with Dr. Tran as our NDCG isn't an effective measure

added dummy continuous model for seeing how continuous works

updated TestRanking to contain calls for continuous model... still have to manually edit when changing between models  - switch between call to performRanking and performContinuousRanking
add dummy continuous model