Update year to 2016

MIT-LICENSE.txt

 The MIT License
 
-Copyright (c) 2009-2015 Robby Russell and contributors (see https://github.com/robbyrussell/oh-my-zsh/contributors)
+Copyright (c) 2009-2016 Robby Russell and contributors (see https://github.com/robbyrussell/oh-my-zsh/contributors)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal