Try Python 3.6 in Travis (#173)

.travis.yml

@@ -6,6 +6,8 @@ python:
     - 3.3
     - 3.4
     - 3.5
+    - 3.6
+    - nightly
 sudo: false
 install:
     - if [[ $TRAVIS_PYTHON_VERSION == '3.2' ]]; then pip install coverage==3.7.1; fi

setup.py

@@ -106,6 +106,7 @@ setup(
         "Programming Language :: Python :: 3.3",
         "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
         "Topic :: Text Processing :: Markup"
     ],
 )