Commented Feature: Ensure Windows Phone 8 developers can use Tweetinvi [2078]

Comments: Associated with changeset 35279: Version 0.9.1.0
- Added async interfaces for objects
- Removed the ability to directly download a file, you now have access to the stream. The reason is that WP, W8 and Mono does not interact with the file the same way and no FIlteredStream is available in WP
- Updated Download image example

To move to a file use Stream.CopyTo
var fileStream = new FileStream("testMe.jpg", FileMode.Create);
stream.CopyTo(fileStream);