Change Travis configuration to use stages in CI

Fix #221

.travis.yml

@@ -1,5 +1,16 @@
 sudo: false
 language: python
+
+notifications:
+  irc:
+    channels:
+    - 'chat.freenode.net#pytest'
+    on_success: change
+    on_failure: change
+    skip_join: true
+  email:
+  - pytest-commit@python.org
+
 python:
 - '2.6'
 - '2.7'
@@ -10,25 +21,24 @@ env:
 - TOXENV=py-pytest30
 - TOXENV=py-pytest31
 - TOXENV=py-pytest32
+
 install: pip install tox setuptools_scm
-matrix:
+script: tox
+
+jobs:
   include:
-  # note: please use "tox --listenvs" to populate the build matrix
+    - stage: test
+    # python x env above are already included into this stage
     - python: "3.6"
       env: TOXENV=flakes
     - python: "3.6"
       env: TOXENV=readme
 
-script: tox
-notifications:
-  irc:
-    channels:
-    - chat.freenode.net#pytest
-    on_success: change
-    on_failure: change
-    skip_join: true
-  email:
-  - pytest-commit@python.org
+    - stage: deploy
+      python: '3.6'
+      env:
+      install: skip
+      script: skip
       deploy:
         provider: pypi
         user: ronny