Provide a skeleton for XSnippet Web app

The skeleton includes NPM, Grunt and Bower configurations. It also
provides a very little entry-point for the future application.

Developer workflow:

    $ npm install               # install dev dependencies
    $ bower install             # install project dependencies

Production workflow:

    $ npm install               # install dev dependencies
    $ grunt build               # get a production-ready copy
Merge pull request #1 from xsnippet/skeleton

Provide a skeleton for XSnippet Web app