-Added a validation and output of invalid opinion words
Merge branch 'master' of https://github.com/dariussuciu/unsupervised-sentiment-analysis
Merge branch 'master' of https://github.com/dariussuciu/unsupervised-sentiment-analysis
Merge branch 'master' of https://github.com/dariussuciu/unsupervised-sentiment-analysis
Merge branch 'master' of https://github.com/dariussuciu/unsupervised-sentiment-analysis
Merge branch 'master' of https://github.com/dariussuciu/unsupervised-sentiment-analysis