iPad multitasking in iOS 9 is surprisingly simple (but huge, too)

Multitasking for the iPad was an iOS 9 feature that prompted whoops of excitement in the WWDC 2015 keynote, but it was quickly followed by concerns that upgrading existing apps might be a nightmare. Turns out, Apple has been eager to explain during its developer event, that couldn't be further from the truth. In fact, if anything the psychological change …