Accept header parsing fixes. Now return first acceptable match rather than last. If not acceptable match in accept, 406 error returns list of acceptable types as text string. application/xml is listed in acceptable types only if dicttoxml is installed. Handle q > 1.0 by demoting q factor to 0.0001 making it unusable. Test cases for all this code. XML is commented out as we don't install dicttoxml.py.

#!/usr/bin/env python

# Roundup requires Python 2.7+ as mentioned in doc\installation.txt
from __future__ import print_function
VERSION_NEEDED = (2,7)

import sys
if sys.version_info < VERSION_NEEDED:
    print("Content-Type: text/plain\n")
    print("Roundup requires Python %s.%s or newer." % VERSION_NEEDED)
    sys.exit(0)