Adding NELL
hi @lhoestq, I wanted to push another change to this branch b/c I found a bug in the parsing. I need to swap arg1 and arg2. I tried to git push -u origin nell but it didn't work. So I tried to do git push --force -u origin nell which seems to work, but nothing is happening to this branch. I think this is because it's closed. Do I need to open another PR?

The change should be below in _generate_examples:
                    best_arg1 = row[9]
                    best_arg2 = row[8]
 Hi @ontocord !

Yup the easiest thing to do is to open a new PR with a title like "Fix NELL dataset argument order". If it's a simple fix we can look at it pretty fast :) 
NELL is a knowledge base and knowledge graph along with sentences used to create the KB. See http://rtw.ml.cmu.edu/rtw/ for more details.