Initial commit

src/util.cpp

@@ -0,0 +1,11 @@
+#include <algorithm>
+#include <cctype>
+
+#include "util.h"
+
+std::string util::lowercase(const std::string &s) {
+  std::string out(s);
+  std::transform(s.begin(), s.end(), out.begin(),
+                 [](unsigned char c) { return std::tolower(c); });
+  return out;
+}