Popover: Using NSPopover to display contents of a view controller

Last Revision:	Version 1.2, 2015-12-17 Updated for OS X 10.11 SDK, replace deprecated APIs, upgraded to use Storyboards. (Full Revision History)
Build Requirements:	OS X 10.11 SDK or later
Runtime Requirements:	OS X 10.10 or later

Demonstrates how to use the NSPopover class by showing how to change the popover type, positioning and animation. It also demonstrates how to detach a given popover to a separate window. To detach it to separate window, drag the popover away from its original position. The popover's content is driven by a NSViewController subclass.