Add testing infrastructure for python 3.6

3.6 was released near the end of 2016 so ought to get it in the
testing loop. Local tests are passing, so this commit checks travis.

.travis.yml

@@ -1,7 +1,7 @@
 sudo: false
 language: python
 python:
-      - "3.5"
+      - "3.6"
 install:
       - pip install tox 
 script:
@@ -11,6 +11,7 @@ env:
       - TOXENV=py33
       - TOXENV=py34
       - TOXENV=py35
+      - TOXENV=py36
       - TOXENV=pypy
       - TOXENV=pep8
       - TOXENV=py35-failskip
@@ -18,6 +19,7 @@ env:
       - TOXENV=py35-prefix
       - TOXENV=py27-pytest
       - TOXENV=py35-pytest
+      - TOXENV=py36-pytest
 
 notifications:
       irc: "chat.freenode.net#gabbi"

README.rst

@@ -20,7 +20,7 @@ looks like this::
 See the docs_ for more details on the many features and formats for
 setting request headers and bodies and evaluating responses.
 
-Gabbi is tested with Python 2.7, 3.4, 3.5 and pypy.
+Gabbi is tested with Python 2.7, 3.4, 3.5, 3.6 and pypy.
 
 Tests can be run using `unittest`_ style test runners, `pytest`_
 or from the command line with a `gabbi-run`_ script.

setup.cfg

@@ -19,6 +19,7 @@ classifier =
     Programming Language :: Python :: 3.3
     Programming Language :: Python :: 3.4
     Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
     Topic :: Internet :: WWW/HTTP :: WSGI
     Topic :: Software Development :: Testing
 

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 1.6
 skipsdist = True
-envlist = py27,py33,py34,py35,pypy,pep8,limit,failskip,docs,py35-prefix,py35-limit,py35-failskip,py27-pytest,py35-pytest
+envlist = py27,py33,py34,py35,py36,pypy,pep8,limit,failskip,docs,py35-prefix,py35-limit,py35-failskip,py27-pytest,py35-pytest,py36-pytest
 
 [testenv]
 deps = -r{toxinidir}/requirements.txt
@@ -21,6 +21,9 @@ commands = py.test gabbi
 [testenv:py35-pytest]
 commands = py.test gabbi
 
+[testenv:py36-pytest]
+commands = py.test gabbi
+
 [testenv:py35-prefix]
 setenv = GABBI_PREFIX=/snoopy