Added basic styling and relevant gulp tasks

This is with regards to #38 and #40. The PR contains a set gulp tasks to consume a basic template (jade and scss -- not sure whether this choice makes sense, but I'd like to hear otherwise) and wrap it over the markdown files to generates a valid `site` with TOC (check attached screenshot).

* Added `generate:site` which generates HTML site by passing markdowns through a template
* Added basic jade template and sass styles
 * Refer `index.jade`
* Added `gulp-layoutize` plugin which wraps the content with a template
 * Supports other templating engines since under the hood it uses consolidate.js

![jyojnnkblh-3000x3000](https://f.cloud.github.com/assets/29519/2243323/1bcd2250-9d27-11e3-966c-c42e2b02ab6d.png)

Feedback appreciated, thanks!