Fix URL to raw gist script in README
Fix URL to raw gist script in README

The curl command line the README currently has just results in the
HTML of a redirect page.

roxyboy/jist,mattn/gist,ConradIrwin/gist,retrography/gist,roxyboy/gist,ConradIrwin/jist,Jwata/gist-old,ConradIrwin/gist,mofodox/gist,defunkt/gist,ryanbradynd05/gist,dLobatog/gist,eLobato/gist,bchase/gist,flores/gist,zmwangx/gist