Update script.py for Python 2's print statement vs. Python 3's function.

Stumbled upon when NetBSD's pkgsrc bulk build tried 3.3: http://ftp.netbsd.org/pub/pkgsrc/misc/joerg/20140123.1827/py33-flask-security-1.7.1/install.log

(And now I see this duplicates #213 except for the first hunk (`__future__`)).