Facia json lite

Adds `/*path/lite.json` for a very minimal view of a front, consisting of headline, url & thumb for three items from each of its containers. Intended as an ajax endpoint for the "Across the Guardian" module. 
```
{
  "webTitle": "Across-the-guardian"
  "collections": [
    {
      "displayName": "Culture",
      "href": "tone/features",
      "content": [
        {
          "headline": "Independent Scotland '£5bn better off by 2030' - live campaign coverage",
          "id": "uk-news/scotland-blog/2014/may/28/danny-alexander-alex-salmond-clash-economy-scotland-live",
          "thumbnail": "http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/5/27/1401223484541/dbdad47e-469d-4ff5-a292-e84f2f8ad67b-140x84.jpeg"
        },
        {
          "headline": "Quiz: How many of these metal album covers do you recognise?",
          "id": "music/musicblog/quiz/2014/may/28/metal-best-albums-how-many-do-you-recognise-heavy-motley-crue-all-time-covers-sleeve",
          "thumbnail": "http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/5/28/1401276866196/mechanical.jpeg"
        },
        {
          "headline": "Shardenfreude: London's copycat craze is crystal clear",
          "id": "artanddesign/architecture-design-blog/2014/may/28/shardenfreude-londons-copycat-craze-is-crystal-clear",
          "thumbnail": "http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/5/28/1401271582236/178f4732-8140-45a9-b1b4-4658de38e6ab-140x84.jpeg"
        }
      ]
    }
    {
      "displayName": "Business",
      "href": "business",
      "content": [
        {
          "headline": "Business live: German unemployment rises, as Merkel confirmed as world's most powerful woman again",
          "id": "business/2014/may/28/markets-rally-china-property-german-unemployment-live",
          "thumbnail": "http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2014/5/28/1401265039553/54a38860-692d-4786-83da-9d94d16ac8b1-140x84.jpeg"
        },

        ... etc ...
```