Temporarily use sources for composer packages

.travis.yml

@@ -49,7 +49,7 @@ before_script:
   - sh -c "if [ '$HHVM' != '1' ]; then phpenv config-rm xdebug.ini; fi"
   - composer self-update
   - if [ -n "$GH_TOKEN" ]; then composer config github-oauth.github.com ${GH_TOKEN}; fi;
-  - composer install --prefer-dist --no-interaction
+  - composer install --prefer-source --no-interaction
 
   - sh -c "if [ '$DB' = 'mysql' ]; then mysql -e 'CREATE DATABASE cakephp_test;'; fi"
   - sh -c "if [ '$DB' = 'mysql' ]; then mysql -e 'CREATE DATABASE cakephp_test2;'; fi"