Support python3.5

[guyskk]

I had looked at .travis.yml but didn't see py35, so I tested it on python3.5 manually, it fail.

here is the outputs:

[guyskk@localhost couchdb-python]$ tox -e py35
GLOB sdist-make: /home/guyskk/couchdb-python/setup.py
py35 inst-nodeps: /home/guyskk/couchdb-python/.tox/dist/CouchDB-1.0.2dev-r0.zip
py35 installed: Warning: cannot find svn location for CouchDB===1.0.2dev-r0,## FIXME: could not find svn URL in dependency_links for this package:,CouchDB===1.0.2dev-r0,simplejson==3.8.2
py35 runtests: PYTHONHASHSEED='3926109077'
py35 runtests: commands[0] | python --version
Python 3.5.1
py35 runtests: commands[1] | /home/guyskk/couchdb-python/.tox/py35/bin/python -m couchdb.tests
...........................................................................................................F..................................................................
======================================================================
FAIL: test_timeout_retry (couchdb.tests.couchhttp.SessionTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/guyskk/couchdb-python/couchdb/tests/couchhttp.py", line 32, in test_timeout_retry
    self.assertRaises(socket.timeout, session.request, 'GET', db.resource.url)
AssertionError: timeout not raised by request

----------------------------------------------------------------------
Ran 174 tests in 39.508s

FAILED (failures=1)
ERROR: InvocationError: '/home/guyskk/couchdb-python/.tox/py35/bin/python -m couchdb.tests'
___________________________________ summary ____________________________________
ERROR:   py35: commands failed

[rdbisme]

Seems a problem with the communication to the couchdb database. Are you sure you can access it?

I tested with python35 and all the tests get passed.

[guyskk]

I test it again but can't reproduce this problem.
Your commit can be merged into this repo, thank you for your good job.

[djc]

@rubendibattista thanks for the patch, applied as 9141667!