Merge branch 'lordelph-master'

# Conflicts:
#	src/Data/Authorization.php

src/Client.php

@@ -55,6 +55,11 @@ class Client
      */
     const VALIDATION_HTTP = 'http-01';
 
+    /**
+     * DNS validation
+     */
+    const VALIDATION_DNS = 'dns-01';
+
     /**
      * @var string
      */