The Caching Server in OS X Server 5 (for El Capitan and Yosemite) now does content and Software Updates. Woohoo, the promised land. Now, when 10 of your users download that latest Nicholas Sparks book and movie, you only sacrifice your WAN pipe to download it once, and the other 9 people piggy-back off that. And when OS X El Capitan ships, you only need to download it over the WAN once, and the other local users will pull off that spiffy Caching Server sitting in your office. Pretty sweet, right? So, how do you use this ultra-complicated service. Well, it looks and feels kinda’ like an iPad app. Which is…