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 
Sorry, I wasn't clear. Is there a particular reason "span" needs to be part of the selector? Aren't the classes unique enough on their own for the purposes of the selector?