Merge pull request #1 from relentlesscoder/feature-QL(Language_Model)

Feature: Ranker QL(language model)
Implemented simple numviews ranker...

1. Reformatted the codes in Evaluator.java
2. Make the labma of QL ranker a constant…
Merge pull request #2 from relentlesscoder/feature-numviews

Implemented simple numviews ranker...
Merge pull request #3 from relentlesscoder/develop

Develop