Add MagePal Core extension

Author: srenon

composer.json

@@ -16,7 +16,7 @@
         "php": "~5.6.0|7.0.2|7.0.4|~7.0.6|~7.1.0|~7.1.3|~7.2.0|~7.3.0",
         "magento/module-backend": "100.0.*|100.1.*|100.2.*|101.0.*",
         "magento/framework": "100.0.*|100.1.*|101.0.*|102.0.*",
-        "magepal/magento2-core":"1.1.*"
+        "magepal/magento2-core":">1.1.0"
     },
     "suggest": {
         "magepal/magento2-preview-checkout-success-page":"Preview checkout success page from admin"