adding an optional tabular view for index page.

[adityashedge]

1. simple navbar with 'api_name'
2. all api calls for resource listed in table with api details in columns
   column1 contains http method and route url combination(eg: 'GET /api/orders') and column2 contains 'description'(spec example name)
3. option to choose between tabular view or the current view
4. change also requires route url and http method info in index.json which will in turn be saved in 'IndexExample' instance

sample index.json file looks like below

{
  "resources": [
    {
      "name": "Orders",
      "examples": [
        {
          "description": "Creating an order",
          "link": "orders/creating_an_order.json",
          "groups": "all",
          "route": "/orders",
          "method": "post"
        },
        {
          "description": "Deleting an order",
          "link": "orders/deleting_an_order.json",
          "groups": "all",
          "route": "/orders/:id",
          "method": "delete"
        }
      ]
    }
  ]
}