Add new Getting Started page

Modified content in start-en.hbs to match the new theme, 
Added page specific css in content/_base,scss
Modified colours in main/_base.scss and footer/_base.scss
Modified link colours in _variables.scss 
@pjackson28 I was following the indentation errors that Travis build was notifying, I'm not sure if it's the Sublime editor then that could be the problem or Travis.