add "write_to" parameter to wml_message

"write_to" lets the wmldev specify to where the message should be
written. Defaults to the previous behaviour.

The intention is for example that one might want to give a summary  as a
chat message and a very detailed information in the stderr file.

src/game_events/action_wml.cpp

@@ -593,8 +593,9 @@ void handle_wml_log_message(const config& cfg)
 {
 	const std::string& logger = cfg["logger"];
 	const std::string& msg = cfg["message"];
+	const std::string& type = cfg["write_to"];
 
-	put_wml_message(logger,msg);
+	put_wml_message(logger,msg,type);
 }
 
 

src/game_events/pump.cpp

@@ -373,6 +373,19 @@ namespace { // Support functions
 		show_wml_messages(wml_messages_stream, caption, false);
 	}
 
+	void put_wml_message(lg::logger& logger, const std::string& prefix, const std::string& message, const std::string& type)
+	{
+		if (type != "chat")
+		{
+			logger(log_wml) << message << "\n";
+		}
+		if (type != "console")
+		{
+			wml_messages_stream << prefix << message << "\n";
+		}
+	}
+
+
 } // end anonymous namespace (support functions)
 
 
@@ -401,20 +414,16 @@ context::scoped::~scoped()
  * Helper function which determines whether a wml_message text can
  * really be pushed into the wml_messages_stream, and does it.
  */
-void put_wml_message(const std::string& logger, const std::string& message)
+void put_wml_message(const std::string& logger, const std::string& message, const std::string& type)
 {
 	if (logger == "err" || logger == "error") {
-		ERR_WML << message << "\n";
-		wml_messages_stream << _("Error: ") << message << "\n";
+		put_wml_message(lg::err, _("Error: "), message, type );
 	} else if (logger == "warn" || logger == "wrn" || logger == "warning") {
-		WRN_WML << message << "\n";
-		wml_messages_stream << _("Warning: ") << message << "\n";
+		put_wml_message(lg::warn, _("Warning: "), message, type );
 	} else if ((logger == "debug" || logger == "dbg") && !lg::debug.dont_log(log_wml)) {
-		DBG_WML << message << "\n";
-		wml_messages_stream << _("Debug: ") << message << "\n";
+		put_wml_message(lg::debug, _("Debug: "), message, type );
 	} else if (!lg::info.dont_log(log_wml)) {
-		LOG_WML << message << "\n";
-		wml_messages_stream << _("Info: ") << message << "\n";
+		put_wml_message(lg::info, _("Info: "), message, type );
 	}
 }
 

src/game_events/pump.hpp

@@ -97,7 +97,8 @@ namespace game_events
 
 	/// Helper function which determines whether a wml_message text can
 	/// really be pushed into the wml_messages_stream, and does it.
-	void put_wml_message(const std::string& logger, const std::string& message);
+	/// @param type: "console" for logging into console, "chat" for logging into chat, every other value for loggign into both.
+	void put_wml_message(const std::string& logger, const std::string& message, const std::string& type = "both");
 
 	/**
 	 * Directly runs the lua command(s) @a lua_code