CS193p Winter 2016-17 (based on iOS 10 and Swift 3) will be available on iTunesU starting a few weeks after the beginning of the quarter.
CS193p was last offered (based on iOS 9 and Swift 2.2) in Spring 2015-16. It is available on iTunesU.
The website you are looking at (http://cs193p.stanford.edu) was retired a few years ago, but evidently iTunesU folks still need it for demo code downloads, so that code for last Spring's iOS 9/Swift 2.2 version (not including the Calculator demos) is posted below. Swift 3 has since been released and so the demo code below will have some incompatibilities that you'll have to resolve.
Please do not repost from this website on other websites--these downloads are for the individual use of those of you watching the course on iTunesU. Enjoy!