adjusting existing tile css to fit design,
- use flexbox where possible to have equal
  height tiles
- override hover and focus states for links
  to ensure links have correct colour
integrate tile markup into homepage layout

- removed any concept of password protection in templates
  and removed the option in the admin to password protect
  an article
- removed rspec tests which deal with seeing password
  protection in the frontend
added title attribute to header links for tiles
improved random class selector with credit to Ben L
Merge pull request #53 from moneyadviceservice/tiles

Tiles