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 
@burgvan This should be limited to just the affected pages until at which time it has been properly tested and any needed fixes have been made on other pages. It can be expanded at a later date but global changes are very risky which is why it is good to roll out the changes slowly (page by page) so we can identify and fix issues as we go (versus getting a barrage of issues filed for unexpected bugs on other pages).