Update `download` example in Readme

[Phlippie]

The Readme provides the following example for saving objects to file:

let destination: NSURL = FileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
amazonS3Manager.download(at: "myFolder/fileName.jpg", to: destination)

This code doesn't compile in Swift 3. The file manager API is outdated, and it seems that the download method does not accept an NSURL as its to: parameter. Please update with a working example.

Been using this library for a while and really like it. Migrating to Swift 3 is just a PITA in general. Cheers!

[Anthony Miller]

Thanks for the kind words and the heads up! I
l'll get to this soon.

[Saqib]

Any update on this issue?

[Anthony Miller]

This has been fixed. The README will now show the correct way to download files using the latest version of Alamofire.

[Phlippie]

@AnthonyMDev Awesome! Thanks!