Merge branch 'develop'
Refactored the evaluator....
Update eval, added output string
Fixed a bug for calculating NDCG
Merge pull request #11 from relentlesscoder/feature-evaluator

Feature evaluator
Revert "Feature evaluator"
Merge pull request #12 from relentlesscoder/revert-11-feature-evaluator

Revert 11 feature evaluator