data export commit, supports exporting task history via csv

*adds the following new dependencies: moment, express-csv
*recommend replacing functionality of 'relative-date' with features from 'moment'
*supports retrieval of CSV history via the API and in browser
**/api/v1/export/history (requires typical API authorization)
**/export/history.csv (requires session authorization)
*adds new routes for data export

src/controllers/dataexport.js

@@ -0,0 +1,51 @@
+var _ = require('lodash');
+var csv = require('express-csv');
+var User = require('../models/user').model;
+var nconf = require('nconf');
+var moment = require('moment');
+var dataexport = module.exports;
+
+
+/*
+  ------------------------------------------------------------------------
+  Data export
+  ------------------------------------------------------------------------
+*/
+
+dataexport.history = function(req, res) {
+  var user = res.locals.user;
+  var output = [
+    ["Task Name", "Task ID", "Task Type", "Date", "Value"]
+  ];
+  _.each(user.tasks, function(task) {
+    _.each(task.history, function(history) {
+      output.push(
+        [task.text, task.id, task.type, moment(history.date).format("MM-DD-YYYY HH:mm:ss"), history.value]
+      );
+    });
+  });
+  return res.csv(output);
+}
+
+dataexport.auth = function(req, res, next) { //[todo] there is probably a more elegant way of doing this...
+  var uid;
+  uid = req.session.userId;
+  if (!(req.session && req.session.userId)) {
+    return res.json(401, "You must be logged in.");
+  }
+  return User.findOne({
+    _id: uid,
+  }, function(err, user) {
+    if (err) {
+      return res.json(500, {
+        err: err
+      });
+    }
+    if (_.isEmpty(user)) {
+      return res.json(401, "No user found.");
+    }
+
+    res.locals.user = user;
+    return next();
+  });
+};