Swift Unwrapped

Error Handling: https://github.com/apple/swift/blob/master/docs/ErrorHandling.rst Rationale and Proposal: https://github.com/apple/swift/blob/master/docs/ErrorHandlingRationale.rst Swift 2.0 blog post: https://developer.apple.com/swift/blog/?id=29 Cocoa error handling: https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/ErrorHandlingCocoa/ErrorHandling/ErrorHandling.html Typed throws vs not discussed in Swift Weekly Brief #68 and #51