Update to Handle 5.x

Reduce deployment target to iOS 9.0

Update Cartfile to use workaround branch for Async framework

* This is to work around an issue with the current upstream
  master that leads to apps being rejected due to incorrect
  CFBundleVersion error.

Update for Xcode 8.1 / Swift 3.0.1

Swift 3

Added icon for iOS demo app.

Changed queue from background to userInteractive to speed up the copy.

The default progress handler now uses the max progress statistic.

Added min and max progress statistics to the progress object.

Carthage support.

Replaced two variables with constants to silence compiler warnings.

Shared the framework scheme to enable installation from Carthage.

The default for swiftyCopyItemAtPath is now to continue as a background task.

Changed the API (copyItemAtPath → swiftyCopyItemAtPath) to remove ambiguity with original method after making progressHandler argument optional.

Initial release. For Swift 2.2 and above.