Adds interesting links to countries index
Correct display of countries list on mobile
Corrects placement of rankings button on countries index
Improves CSS structure
Merge branch 'feature/landing-page' into feature/mobile-country-page

* feature/landing-page:
  Country: menu updated and buttons removed
  Howto: names and urls updated
  Keep Updated: names updated

Conflicts:
	app/views/countries/index.html.erb
Avoiding changing site-wide layout to fix one page
Removes left-over testing CSS
Merge pull request #1114 from Vizzuality/feature/mobile-country-page

Responsive country page