Travis CI: before_script should be install.
Travis CI: Overwrite before_install step. Default currently fails on PHP 5.2.
Merge pull request #445 from bantu/travis-ci-install

Travis CI: before_script should be install. Overwrite before_install for 5.2.

* bantu/travis-ci-install:
  Travis CI: Overwrite before_install step. Default currently fails on PHP 5.2.
  Travis CI: before_script should be install.