Remove iteritems() calls if Python 3 compatibility is desired

[guidovranken]

Python 3 does not support the iteritems() for the dict object:

$ cat p.py 
d = {'x':10, 'y':20}
for k, v in d.iteritems():
    print(k,v)
$ python2 -V
Python 2.7.6
$ python2 p.py 
('y', 20)
('x', 10)
$ python3 -V
Python 3.4.0
$ python3 p.py 
Traceback (most recent call last):
  File "p.py", line 2, in <module>
    for k, v in d.iteritems():
AttributeError: 'dict' object has no attribute 'iteritems'

So if you want libtaxii to work with Python 3, these calls have to be replaced or made possible by using six. If achieving Python 3 compatibility is deliberately avoided for now, then you can disregard this report. (I couldn't find any explicit mention about this).

libtaxii-master$ find -name '*.py' -exec grep -Hn iteritems {} \;

./libtaxii/messages_10.py:410:        for k, v in self.extended_headers.iteritems():
./libtaxii/messages_10.py:428:        for k, v in self.extended_headers.iteritems():
./libtaxii/messages_10.py:498:        for k, v in d['extended_headers'].iteritems():
./libtaxii/common.py:311:                for k, v in self_value.iteritems():
./libtaxii/taxii_default_query.py:708:        for k, v in self.parameters.iteritems():
./libtaxii/clients.py:215:            for k, v in headers.iteritems():
./libtaxii/__init__.py:83:        header_dict = http_response.info().dict.iteritems()
./libtaxii/messages_11.py:1073:        for k, v in self.extended_headers.iteritems():
./libtaxii/messages_11.py:1088:        for k, v in self.extended_headers.iteritems():
./libtaxii/messages_11.py:1145:        for k, v in d['extended_headers'].iteritems():
./libtaxii/messages_11.py:2970:        for sd_name, rules in detail_rules.iteritems():
./libtaxii/messages_11.py:2993:            for k, v in self.status_detail.iteritems():
./libtaxii/messages_11.py:3022:        for k, v in self.status_detail.iteritems():

[MarkDavidson]

I think working with Python 3 is a nice to have, at least for now. If these are the only things preventing Python 3 compatibility, then I think these changes are no brainers to make. Otherwise, I'd be interested in what the full scope of changes required are for Python 3 compatibility.

-Mark