Ensure PHP 5.5 for ::class notation

composer.json

@@ -3,6 +3,7 @@
         "dflydev/embedded-composer": "^1.0@dev",
         "opdavies/sculpin-content-generator-bundle": "@stable",
         "opdavies/sculpin-gist-embed-bundle": "dev-master",
+        "php": "^5.5",
         "sculpin/sculpin": "^2.1@dev",
         "tsphethean/sculpin-related-posts-bundle": "~0.1.0"
     },

composer.lock

@@ -4,8 +4,8 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "55148cddcce0e9a55f92fad0394fdada",
-    "content-hash": "9add10c78a4b2732183fabe01383449c",
+    "hash": "5e30cc558060688649540ceb733270b2",
+    "content-hash": "aed2c9fa91ef1e3f65996527ec243fc5",
     "packages": [
         {
             "name": "composer/ca-bundle",
@@ -3665,6 +3665,8 @@
     },
     "prefer-stable": false,
     "prefer-lowest": false,
-    "platform": [],
+    "platform": {
+        "php": "^5.5"
+    },
     "platform-dev": []
 }