Closes #73 - allowing for projects to be hidden from public view

The hope for this PR is to make getting projects live a bit easier, at least with a bit less copy and pasting... 

* projects are set as not public by default (they are still available for users given the URL to review)
* when a project is not public we include the URL in the robots.txt to disallow
* there is now an epic robots.txt 
* when we want a project to go live we flip the switch in the admin