add missing includes, cleanup

Change-Id: Ifea313cc529a6c21c040b99748b2b5f502d021fe
diff --git a/include/ice_options.h b/include/ice_options.h
index 1bdc760..d3a9e83 100644
--- a/include/ice_options.h
+++ b/include/ice_options.h
@@ -1,10 +1,11 @@
 #pragma once
 
+#include "ip_utils.h"
+
 #include <functional>
 #include <vector>
 #include <string>
-
-#include "ip_utils.h"
+#include <memory>
 
 namespace dhtnet {