Add Urdu Sentiment Corpus (USC). 
@lhoestq have made the suggested changes in the README file. @lhoestq Created a new PR #1231 with only the relevant files.
closing this one :)
Added Urdu Sentiment Corpus. More details about the dataset over <a href="https://github.com/MuhammadYaseenKhan/Urdu-Sentiment-Corpus">here</a>. 