usql update

usql/settings.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <string>
+#include <map>
+
+namespace usql {
+
+class Settings {
+
+public:
+    static void set_setting(const std::string &name, const std::string &value);
+    static std::string get_setting(const std::string &name);
+
+    static long string_to_date(const std::string &datestr);
+    static std::string date_to_string(long date);
+    static std::string double_to_string(double d);
+    // TODO add bool_to_string and use it in ColBooleanValue
+
+private:
+    static std::vector<std::pair<std::string, std::string>> m_settings;
+};
+
+}	// namespace