[#7] Move installation of tourexec to before_install

Author: meatballs

.travis.yml

@@ -7,11 +7,11 @@ before_install:
   - sh -e /etc/init.d/xvfb start
   - sudo apt-get -qq update
   - sudo apt-get install gfortran
-install:
-  - pip install -r requirements.txt
-  - pip install pytest
   - git clone https://github.com/Axelrod-Python/TourExec.git /tmp/TourExec
   - cd /tmp/TourExec
   - make install
+install:
+  - pip install -r requirements.txt
+  - pip install pytest
 script:
     - pytest