Modernized the Travis configuration

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index 229e133..4881cc9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,21 +1,34 @@
-dist: trusty
 language: python
 
-python:
-  - "2.6"
-  - "2.7"
+stages:
+  - name: test
+  - name: deploy to PyPI
+    if: type = push AND tag =~ ^\d+\.\d+\.\d+
 
-install: pip install tox-travis
+jobs:
+  include:
+    - stage: test
+      env: TOXENV=py26
+      dist: trusty
+      python: "2.6"
+
+    - stage: test
+      env: TOXENV=py27
+      python: "2.7"
+
+    - stage: deploy to PyPI
+      install: true
+      script: skip
+      deploy:
+        provider: pypi
+        user: agronholm
+        password:
+          secure: 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
+        distributions: sdist bdist_wheel
+        on:
+          tags: true
+          repo: agronholm/pythonfutures
+
+install: pip install tox
 
 script: tox
-
-deploy:
-  provider: pypi
-  user: agronholm
-  password:
-    secure: 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
-  distributions: sdist bdist_wheel
-  on:
-    tags: true
-    repo: agronholm/pythonfutures
-    python: "2.7"