Python 3.X changes using 2to3 lib

[joseboveda]

Fair warning, haven't tested this thoroughly so please review!

[paulmakepeace]

@joseboveda - have you run tests etc? Apologies for the extra late response...

[felixlohmeier]

test results for Python 3.7.3

• 2.0-java6: FAILED (errors=17)
• 2.5-java7: FAILED (errors=17)
• 3.2-java11: FAILED (errors=17)

two types of errors (for now):

1. refine.py line 84: urllib.request.urlopen(req)

Traceback (most recent call last):
  File "/home/felix/Desktop/refine-client-py/tests/refinetest.py", line 39, in setUp
    project_file=self.project_path(), project_format=self.project_format, **self.project_options)
  File "/home/felix/Desktop/refine-client-py/google/refine/refine.py", line 273, in new_project
    'create-project-from-upload', options, params
  File "/home/felix/Desktop/refine-client-py/google/refine/refine.py", line 84, in urlopen
    response = urllib.request.urlopen(req)
  File "/usr/lib64/python3.7/urllib/request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib64/python3.7/urllib/request.py", line 525, in open
    response = self._open(req, data)
  File "/usr/lib64/python3.7/urllib/request.py", line 543, in _open
    '_open', req)
  File "/usr/lib64/python3.7/urllib/request.py", line 503, in _call_chain
    result = func(*args)
  File "/usr/lib64/python3.7/urllib/request.py", line 1345, in http_open
    return self.do_open(http.client.HTTPConnection, req)
  File "/usr/lib64/python3.7/urllib/request.py", line 1317, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
  File "/usr/lib64/python3.7/http/client.py", line 1244, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib64/python3.7/http/client.py", line 1290, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib64/python3.7/http/client.py", line 1239, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib64/python3.7/http/client.py", line 1064, in _send_output
    + b'\r\n'
TypeError: can't concat str to bytes

2. refine.py line 93: gzip_fp = gzip.GzipFile(fileobj=StringIO.StringIO(response.read())

Traceback (most recent call last):
  File "/home/felix/Desktop/refine-client-py/tests/test_refine.py", line 31, in test_list_projects
    projects = self.refine.list_projects()
  File "/home/felix/Desktop/refine-client-py/google/refine/refine.py", line 140, in list_projects
    return self.server.urlopen_json('get-all-project-metadata')['projects']
  File "/home/felix/Desktop/refine-client-py/google/refine/refine.py", line 100, in urlopen_json
    response = json.loads(self.urlopen(*args, **kwargs).read())
  File "/home/felix/Desktop/refine-client-py/google/refine/refine.py", line 93, in urlopen
    gzip_fp = gzip.GzipFile(fileobj=StringIO.StringIO(response.read()))
AttributeError: type object '_io.StringIO' has no attribute 'StringIO'