Changed the copyright
I've updated the current copyright to 2018, which that hasn't changed around 3 months.
MIT License
-Copyright (c) 2017 Google Inc., OpenAI and Pennsylvania State University
+Copyright (c) 2018 Google Inc., OpenAI and Pennsylvania State University
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
