HttpResponse returns data as byte strings, and in Python 2.x we could

generally just check against those without problems, but on Python 3.x

the different string types are less compatible. We now convert the

responses to Unicode strings using Django's force_text() (which

intelligently performs a decode when necessary).
We also convert the result of pkg_resources.resource_stream for the

DMARC code, for use in PublicSuffixList. Rather than a straight text

conversion, we need to make use of codecs.getreader(), which will

correctly convert the data in the stream to the right format.

Unit tests pass on Python 2.7, 3.4, 3.5, and 3.6.