Add type-safe wrapper around MD_STD

MD_STD.php

@@ -67,6 +67,20 @@ class MD_STD {
 
     }
 
+    /**
+     * Type safe wrapper around ob_get_clean():  Gets the current buffer
+     * contents and delete current output buffer.
+     *
+     * @return string
+     */
+    public static function ob_get_clean():string {
+
+        $output = ob_get_clean();
+        if ($output === false) throw new MDOutputBufferNotStarted("Output buffer was not started");
+        return $output;
+
+    }
+
     /**
      * Function checking if a string starts with another.
      *