Gnulib copyright updates for 2015

[Paul Eggert]

I updated Gnulib's copyright date to 2015.  Happy new year!

As the patch is rather large I'm not including it in this email, but here is a 
URL:

http://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=b9bfe78424b871f5b92e5ee9e7d21ef951a6801d