Merge pull request #17 from twisty/issue-16

Allow using version 6 of PHP-DI.

Author: mnapoli

composer.json

@@ -10,7 +10,7 @@
         }
     },
     "require": {
-        "php-di/php-di": "~5.0"
+        "php-di/php-di": "~5.0 || ~6.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^3.7"