Simplified instance creation and updated tour

The Oneslate private instance creation form has been simplified to 3 fields and moved to the homepage.  Also, you can now create many instances per email address right from the self-service new instance form.  It should now be easier to create instances as needed.

In addition, the new tour page is an non-comprehensive run-through of what the application interface is like. It contains screenshots indicating some of the visual updates mentioned in the last post.