Updated README for grammar extractor.
Updated README for grammar extractor.

kho/mr-cdec,kho/mr-cdec,pks/cdec-dtrain-legacy,pks/cdec-dtrain-legacy,pks/cdec-dtrain-legacy,pks/cdec-dtrain-legacy,pks/cdec-dtrain-legacy,kho/mr-cdec,kho/mr-cdec,kho/mr-cdec,pks/cdec-dtrain-legacy,kho/mr-cdec