Add standard logging

The added logging strategy uses `stdout` and `stderr` of the
application's process.

issue: #4

app.js

@@ -20,6 +20,7 @@ var pkg = require('./package.json');
 // module variables
 var app = express();
 var debug = Debug('mmtc-ke:app');
+var logger = engine.clients.getLogger();
 var nunjucksEnv;
 
 
@@ -75,7 +76,7 @@ app.use(function(req, res, next) {
 
 debug('mounting middleware for error handling');
 app.use(function(err, req, res, next) {
-    console.error(err);
+    logger.error(err);
     return routes.utils.renderPage(req, res, 'error', {
         error: err,
     });
@@ -84,5 +85,6 @@ app.use(function(err, req, res, next) {
 
 debug('starting server');
 app.listen(config.get('server.port'), config.get('server.ip'), function() {
+    logger.info('server listening');
     debug('server started at http://%s:%s', config.get('server.ip'), config.get('server.port'));
 });

engine/clients.js

@@ -0,0 +1,25 @@
+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2016 Forfuture LLC
+ *
+ * Client to support services.
+ */
+
+
+exports = module.exports = {
+  getLogger: getLogger,
+};
+
+
+// npm-installed modules
+var winston = require('winston');
+
+
+/**
+ * Return the main application logger
+ *
+ * @return {Object} logger
+ */
+function getLogger() {
+  return winston;
+}

engine/index.js

@@ -7,6 +7,7 @@
 
 
 // own modules
+var clients = require('./clients');
 var errors = require('./errors');
 var math = require('./math');
 var networks = require('./networks');
@@ -15,6 +16,7 @@ var networks = require('./networks');
 exports = module.exports = {
   init: init,
 
+  clients: clients,
   errors: errors,
   math: math,
   networks: networks,

package.json

@@ -15,7 +15,8 @@
     "express": "4.13.x",
     "forever": "^0.15.1",
     "lodash": "^4.6.1",
-    "nunjucks": "^2.3.0"
+    "nunjucks": "^2.3.0",
+    "winston": "^2.2.0"
   },
   "repository": {
     "type": "git",