Delete unused data

data/training-data/dev/news-test2008-ref.de.sgm

data/training-data/dev/news-test2008-ref.en.sgm

data/training-data/dev/news-test2008-src.de.sgm

data/training-data/dev/news-test2008-src.en.sgm

data/training-data/dev/news-test2008.de

data/training-data/dev/news-test2008.en

data/training-data/dev/newsdev2014-ref.en.sgm

data/training-data/dev/newsdev2014-src.en.sgm

data/training-data/dev/newsdev2014.en

data/training-data/dev/newssyscomb2009-ref.de.sgm

data/training-data/dev/newssyscomb2009-ref.en.sgm

data/training-data/dev/newssyscomb2009-src.de.sgm

data/training-data/dev/newssyscomb2009-src.en.sgm

data/training-data/dev/newssyscomb2009.de

data/training-data/dev/newssyscomb2009.en

data/training-data/dev/newstest2009-ref.de.sgm

data/training-data/dev/newstest2009-ref.en.sgm

data/training-data/dev/newstest2009-src.de.sgm

data/training-data/dev/newstest2009-src.en.sgm

data/training-data/dev/newstest2009.de