Test in Python 3.6

Signed-off-by: NJames Myatt <james@jamesmyatt.co.uk>

.travis.yml

@@ -3,6 +3,7 @@ sudo: false
 language: python
 
 python:
+  - 3.6
   - 3.5
   - 3.4
   - 3.3

setup.py

@@ -45,6 +45,7 @@ setup(
         'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
         'Topic :: Communications',
         'Topic :: Internet',
     ],