Merge pull request #2005 from ThomasWaldmann/fix-travis-osx-builds

travis: fix OS X based testing

.travis/install.sh

@@ -17,7 +17,7 @@ if [[ "$(uname -s)" == 'Darwin' ]]; then
     brew install lz4
     brew outdated pyenv || brew upgrade pyenv
     brew install pkg-config
-    brew install Caskroom/versions/osxfuse
+    brew install Caskroom/cask/osxfuse
 
     case "${TOXENV}" in
         py34)
@@ -28,6 +28,10 @@ if [[ "$(uname -s)" == 'Darwin' ]]; then
             pyenv install 3.5.1
             pyenv global 3.5.1
             ;;
+        py36)
+            pyenv install 3.6.0
+            pyenv global 3.6.0
+            ;;
     esac
     pyenv rehash
     python -m pip install --user 'virtualenv<14.0'