Display first cause of AggregateException in stacktraces

Currently if an uncaught AggregateException is thrown, the stacktrace shows no cause and the stacktrace points to the creation of AggregateException.

Now it'll display the first exception in the list of causes in the stacktrace as the cause to allow developers to debug their application, even if they can only do it one at a time...
Yeah this is a better solution. 

I was originally thinking that it might cause an issue if a developer happened to already be using this method and was looking for a specific error type, but those developers would also be using the old constructor that only accepted `Exception`s too.

You're solution allows a developer to see some kind of output even if they accidentally use this deprecated method.