Prettier application down/Maintenance/503 screen

With the new default welcome screen, I decided that the "Be back in a minute" just wouldn't work. So, based off of the welcome screen, I made the new and improved 503 screen.
![screen shot 2014-12-06 at 6 24 50 pm](https://cloud.githubusercontent.com/assets/5386772/5329490/3fd2808a-7d75-11e4-91af-e34bc10ca758.png)

It is based off of the welcome screen in the jumbotron part, however it doesn't have the steps.

I also modified the default layout to add a couple of lines that disable the navigation links if the variable down  exists. On the top of 503.blade.php I have @extends('app', ['down'=>true]) , passing it in. As long as you don't use the variable down in your projects, this shouldn't harm anything.

Upon clicking refresh your page, it calls location.reload() , which should refresh the page and bring back the page if you had put the application down.

Upon clicking the email address, it will open a mailto link.

I'm open to criticism, this is my first pull request to a major project. The only problem I see may be that this is too complex for a down screen, however I think that it is basic enough.