[API Notes] Address outstanding nullability issues + new audited pieces
[API Notes] Address outstanding nullability issues + new audited pieces

<rdar://problem/17902944> UIView's motionEffects property should never return 'nil'
<rdar://problem/17971360> [factor-init] SKPhysicsJointPin's factory method is not converted to a Swift API initializer
<rdar://problem/18553910> #IUO UICollectionViewUpdateItem properties
<rdar://problem/18875692> NSEntityDescription subentities/subentitiesByName should be marked optional
<rdar://problem/18919879> Swift: NSTableView's preparedCellAtColumn(_:row:) should return an optional
<rdar://problem/18940072> NSPredicate's init(format:) should not be optional
<rdar://problem/18987481> NSURLRequest without NSURL crashes Swift
<rdar://problem/19034448> UIPrintInfo’s -init is banned, should use +printInfo
<rdar://problem/19147412> NSUserInterfaceItemIdentification declares identifier as a non-optional String and it should be optional or IUO
<rdar://problem/19347931> Declaration of a parameter in Cocoa API in Swift is wrong (NSDateFormatter)
+ additions to the WatchKit audit

+ additions to HealthKit and HomeKit.

Swift SVN r24630

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation