Edit route

I have added a new edit route that allows you to jump directly from blog
posts and pages into the editor (providing you are logged in).
Merge pull request #749 from nblackburn/edit-route

Neat route allowing you to append '/edit' to the url when viewing a page or post to jump into the admin panel;

- Means you don't require access to the ID of the post
- We can add some more front-end features with this
- It does require you to be logged in