Switch over to Universal-Core. (#18)

* Don't build here.

* WIP: Switch to Universal-Core.

* Update Submodule repo & azure-pipelines.

include/utils/stringutils.hpp

@@ -1,4 +1,5 @@
-#pragma once
+#ifndef STRINGUTILS_HPP
+#define STRINGUTILS_HPP
 
 #include "common.hpp"
 
@@ -7,4 +8,6 @@ bool matchPattern(std::string pattern, std::string tested);
 namespace StringUtils
 {
 	std::string format(const std::string& fmt_str, ...);
-}
+}
+
+#endif