re-structured QueryHandler & Ranker
add null ref check
Update the .gitignore

Ignore all unnecessary files for generated by IntelliJ…
Fixed a typo...
Added the rest rankers' skeleton codes
resolve conflicts
Merge branch 'develop' into feature-QL(Language_Model)
Implemented the QL ranker
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...
local commit
implemented vsm - not fully tested
Merge pull request #3 from relentlesscoder/develop

Develop
implement phrase ranker - not fully tested
implement phrase ranker - not fully tested
implement phrase ranker - not fully tested
implement phrase ranker - not fully tested
Added a util class
implement phrase ranker - not fully tested