test to get travis to compile php 5.4-7.0

Author: shinobu

.travis.yml

@@ -4,3 +4,9 @@ php:
   - '5.5'
   - '5.6'
   - '7.0'
+
+before_install:
+  - if [[ ${TRAVIS_PHP_VERSION:0:3} == "5.4" || ${TRAVIS_PHP_VERSION:0:3} == "5.5" ]]; then composer require --dev --no-update phpunit/phpunit ~4; fi
+
+install:
+  - travis_retry composer install --no-interaction --ignore-platform-reqs