Features/edit this page fixes issue #2800

Provides an "Edit this page" link in the site bar, fixes issue #2800 
in this situation it's best to move this out of the `before` block into a `let!`:

```ruby
let!(:root_page) { FactoryGirl.create(:page, :link_url => "/") }
```

Then you can use it:

```ruby
expect(page).to have_link("Edit this page", :href => refinery.edit_admin_page_path(root_page))
```