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 
I believe we were told to put the new css in the wet-boew\theme\content folder because we were not supposed to change main/_base.scss. 

I'm fine with putting the new scss anywhere, I just need to know the location where it works best.

cc/ @thomasgohard 
cc/ @jeresiv