implementing media type negotiation (based on language negotiation

logic) in cases both JSON and (X)HTML are being requested, resolving #68

lib/zerobin.php

@@ -151,7 +151,7 @@ class zerobin
         // output JSON or HTML
         if ($this->_request->isJsonApiCall())
         {
-            header('Content-type: application/json');
+            header('Content-type: ' . request::MIME_JSON);
             header('Access-Control-Allow-Origin: *');
             header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE');
             header('Access-Control-Allow-Headers: X-Requested-With, Content-Type');