Started to port to iOS; fixing compiler errors here and there

src/client/Option.h

@@ -1,7 +1,7 @@
 #pragma once 
 #include <sstream>
 #include <type_traits>
-#include <util/Mth.h>
+#include "Mth.h"
 /*
 template<typename T>
 struct is_option_type : std::false_type {};
@@ -104,4 +104,4 @@ public:
 
 private:
     std::string m_value;
-};
+};