Use Try[X] instead of AsyncResult[X]

[Narigo]

Wouldn't it make sense to use scala.util.Try?
Then a user could pattern match over Success(result) and Failure(exception).

[Narigo]

I've added an implicit Try to AsyncResult in #51 now. This should enable users to pattern match now. Guess that's a better approach as it won't get too far away from the official API to be able to write both.

[Narigo]

As said by @galderz in a [https://github.com//pull/63#discussion-diff-7033174 0.2.0 PR comment], we should explore this for 0.3.0

[galderz]

Closing this, all async results should be converted to Future returns, so that they are completed with Success, and get a Failure otherwise. So, this really should be part of issue #16