support up to 5.5

Author: wallacemaxters

.travis.yml

@@ -1,6 +1,5 @@
 language: php
 php:
-  - '5.4'
   - '5.5'
   - '5.6'
   - '7.0'
@@ -10,3 +9,4 @@ php:
 install: travis_retry composer install --no-interaction --prefer-source
 
 script: ./vendor/bin/phpunit
+dist: trusty

composer.json

@@ -11,7 +11,7 @@
     ],
     "minimum-stability": "stable",
     "require": {
-        "php" : ">=5.4"
+        "php" : ">=5.5"
     },
     "require-dev" : {
         "phpunit/phpunit": "4.*"