Use simple-phpunit instead of phpunit

To avoid problem with the Yaml constant
http://symfony.com/blog/how-to-solve-phpunit-issues-in-symfony-3-2-applications

.travis.yml

@@ -57,7 +57,6 @@ before_script:
     - if [[ ! $PHP = hhvm* ]]; then echo "memory_limit=-1" >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini; fi;
     # xdebug isn't enable for PHP 7.1
     - if [[ ! $PHP = hhvm* ]]; then phpenv config-rm xdebug.ini || echo "xdebug not available"; fi
-    - if [[ $PHP = 5.5 ]]; then composer require "phpunit/phpunit:4.*" --no-update; fi;
     - composer self-update --no-progress
     - if [[ $DB = pgsql ]]; then psql -c 'create database wallabag_test;' -U postgres; fi;
 
@@ -72,7 +71,7 @@ before_install:
 script:
     - travis_wait bash composer install -o  --no-interaction --no-progress --prefer-dist
     - ant prepare-$DB
-    - if [[ $VALIDATE_TRANSLATION_FILE = '' ]]; then phpunit -v ; fi;
+    - if [[ $VALIDATE_TRANSLATION_FILE = '' ]]; then ./bin/simple-phpunit -v ; fi;
     - if [[ $CS_FIXER = run ]]; then php bin/php-cs-fixer fix src/ --verbose --dry-run ; fi;
     - if [[ $VALIDATE_TRANSLATION_FILE = run ]]; then php bin/console lint:yaml src/Wallabag/CoreBundle/Resources/translations -v ; fi;
     - if [[ $VALIDATE_TRANSLATION_FILE = run ]]; then php bin/console lint:yaml app/Resources/CraueConfigBundle/translations -v ; fi;

composer.json

@@ -90,7 +90,6 @@
         "doctrine/doctrine-fixtures-bundle": "~2.2",
         "doctrine/data-fixtures": "~1.1.1",
         "sensio/generator-bundle": "^3.0",
-        "phpunit/phpunit": "~4.0",
         "symfony/phpunit-bridge": "^3.0",
         "friendsofphp/php-cs-fixer": "~1.9",
         "m6web/redis-mock": "^2.0"