MEAN.io Session Cookie parameters

Continuing with my contribution to the MEAN.io (MongoDB, ExpressJS, AngularJS, and NodeJS) technology stack (or should we say framework by now with the progress it’s been making?) I’ve submitted another pull request to allow setting up MEAN.io session cookie parameters. It is often required for enterprise applications to set session cookie parameters and not rely on Express’s defaults. These parameters are for example the cookie expiration time, and whether the session cookie will require the website to run in an SSL-enabled environment.

This PR adds support for default parameters on the cookie session and allows developers to set them as required globally, or per environment (development, testing, and production). Description on the session cookie parameters themselves have been added as well to make this easy to configure.