Check composer requirements on Travis

Author: lookyman

.travis.yml

@@ -7,5 +7,8 @@ before_script:
   - composer install
 script:
   - vendor/bin/phing
+  - >
+    wget https://github.com/maglnet/ComposerRequireChecker/releases/download/0.2.1/composer-require-checker.phar
+    && php composer-require-checker.phar check composer.json
 after_script:
   - php vendor/bin/coveralls -v