* msg_network.js: Management of message network modules (start/stop/etc.)

* Minor updates to ES6 in some areas
* Better bbs.js startup seq
* Better iterator support for loadModulesForCategory()
* Start work on loading message network modules & tieing in record() (WIP)
* FTN PacketHeader is now a ES6 class
* Various FTN utils, e.g. Via line creation

core/msg_network.js

@@ -0,0 +1,60 @@
+/* jslint node: true */
+'use strict';
+
+//	ENiGMA½
+let loadModulesForCategory	= require('./module_util.js').loadModulesForCategory;
+
+//	standard/deps
+let async					= require('async');
+
+exports.startup			= startup
+exports.shutdown		= shutdown;
+exports.recordMessage	= recordMessage;
+
+let msgNetworkModules = [];
+
+function startup(cb) {
+	async.series(
+		[
+			function loadModules(callback) {
+				loadModulesForCategory('scannerTossers', (err, module) => {
+					if(!err) {
+						const modInst = new module.getModule();
+
+						modInst.startup(err => {
+							if(!err) {
+								msgNetworkModules.push(modInst);
+							}
+						});
+					}
+				}, err => {
+					callback(err);
+				});
+			}
+		],
+		cb
+	);
+}
+
+function shutdown() {
+	msgNetworkModules.forEach(mod => {
+		mod.shutdown();
+	});
+
+	msgNetworkModules = [];
+}
+
+function recordMessage(message, cb) {
+	//
+	//	Give all message network modules (scanner/tossers)
+	//	a chance to do something with |message|. Any or all can
+	//	choose to ignore it.
+	//
+	async.each(msgNetworkModules, (modInst, next) => {
+		modInst.record(message, err => {
+			next();
+		});
+	}, err => {
+		cb(err);
+	});
+}