Implement "stats" page with server-side delay

[msgilligan]

index.html links to stats.html which should behave like stats.gtpl (for Gaelyk/Google App Engine)

https://github.com/iui/iui-seed-ratpack/blob/master/src/ratpack/public/stats.html
https://github.com/iui/iui-seed-ratpack/blob/master/src/ratpack/public/stats.gtpl

The 2-second delay is to demonstrate the ajax-loading spinner in iUI. I don't know how to implement a delay on (asynchronous) Ratpack.

I realize this is not strictly necessary for a "seed" application, but it is functionality in the current iUI Music sample, that I would like to see implemented on Ratpack.