Trying to get OS X builds on Travis CI

Author: pawelad

.travis.yml

@@ -1,8 +1,29 @@
 language: python
 
-os:
-  - linux
-  - osx
+matrix:
+    include:
+        - os: linux
+          python: 2.7
+          env: TOXENV=py27
+        - os: linux
+          python: 3.4
+          env: TOXENV=py34
+        # Use generic language for OS X
+        - os: osx
+          language: generic
+          env: TOXENV=py27
+        - os: osx
+          language: generic
+          env: TOXENV=py34
+
+# Perform the manual Python installation steps on OS X
+before_install:
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update          ; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ "$TOXENV" == "py27" ]]; then brew install python; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ "$TOXENV" == "py34" ]]; then brew install python3; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ "$TOXENV" == "py27" ]]; then virtualenv venv -p python; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ "$TOXENV" == "py34" ]]; then virtualenv venv -p python3; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then source venv/bin/activate; fi
 
 install:
   - pip install tox --use-mirrors