Merge pull request #86 from alexmmm/extend-travis-conf

add specific php version 5.3.3 to travis build to validate issue #84

Author: justinrainbow

.travis.yml

@@ -1,14 +1,15 @@
 language: php
 
 php:
+  - 5.3.3
   - 5.3
   - 5.4
   - 5.5
 
 before_script:
   - sudo apt-get -y install pypy python-sphinx graphviz
   - composer selfupdate
-  - composer install
+  - composer install --prefer-source
 
 script:
   - cd docs && make linkcheck && cd ..