Make urllib/urlparse imports Py3 compatible

The urlencode function moved in Python 3, as did the urlparse library.
This commit ensures that both are referenced through the `nsq._compat`
module.

nsq/_compat.py

@@ -32,3 +32,10 @@ def to_bytes(x, charset='utf-8', errors='strict'):
         if isinstance(x, unicode):
             return x.encode(charset, errors)
         raise TypeError('expected bytes or a string, not %r' % type(x))
+
+try:
+    from urllib import parse as urlparse
+    from urllib.parse import urlencode
+except ImportError:
+    import urlparse
+    from urllib import urlencode

nsq/reader.py

@@ -3,9 +3,7 @@
 import logging
 import time
 import functools
-import urllib
 import random
-import urlparse
 import cgi
 import warnings
 import inspect
@@ -20,6 +18,8 @@
 
 from ._compat import string_types
 from ._compat import to_bytes
+from ._compat import urlencode
+from ._compat import urlparse
 from .backoff_timer import BackoffTimer
 from .client import Client
 from . import protocol
@@ -573,7 +573,7 @@ def query_lookupd(self):
 
         params = cgi.parse_qs(query)
         params['topic'] = self.topic
-        query = urllib.urlencode(_utf8_params(params), doseq=1)
+        query = urlencode(_utf8_params(params), doseq=1)
         lookupd_url = urlparse.urlunsplit((scheme, netloc, path, query, fragment))
 
         req = tornado.httpclient.HTTPRequest(