`universal_newlines` changed in Python 3.3

For what I experienced, the worse. Remove it for now to fix #6

http://docs.python.org/3/library/subprocess.html?highlight=popen#frequently-used-arguments

> Changed in version 3.3: When universal_newlines is True, the class uses the encoding locale.getpreferredencoding(False) instead of locale.getpreferredencoding(). See the io.TextIOWrapper class for more information on this change.
Update Autoprefixer to 0.4.20130528