Base NodeJS web application

This PR sets up a web application using [HapiJS](http://spumko.github.io/), a production ready and growing alternative to ExpressJS for NodeJS application development. Hapi is compelling because it is configuration-centric, modular and with off-the-shelf solutions fit to our use case (caching, authentication, batch requests, scalability). Like Express, it doesn't impose a project structure so we are free to organize our application in the sanest way we see fit. It was developed by the creator of [OAuth](http://en.wikipedia.org/wiki/OAuth), and has been used in huge scale production projects (it supports Walmart's entire mobile infrastructure and served them over Black Friday).

Other dependencies:
* GulpJS
*  node-sass: a Node.js wrapper for [libsass](http://libsass.org/), a C/C++ implementation of Ruby SASS that is orders of magnitudes faster

Notable absences:
* Any client-side JavaScript frameworks/libraries
* Script loaders, minifiers, assets strategy for JS
* Test framework and tests (not much to test right now)

Coming
* Bower integration for management of client-side packages
* Browserify integration?

@hakubo and @federico-lox