Context.DI().ActorOf shouldn't require a parameterless constructor

[nvivo]

The new extension method in 1.0 to instantiate actors using DI fails to instantiate any actor that requires parameters because of the "new()" constraint on the extension.

Example:

public class SomeActor : ReceiveActor
{
    public SomeActor(IDependency dependency) { ... }
}

Context.DI().ActorOf<SomeActor>("foo");

Fails with:

'SomeActor' must be a non-abstract type with a public parameterless
constructor in order to use it as parameter 'TActor' in the generic type
or method 'DIActorContextAdapter.ActorOf<TActor>(string)'

This defeats the purpose of the extension.

[rogeralsing]

https://github.com/akkadotnet/akka.net/blob/dev/src/contrib/dependencyInjection/Akka.DI.Core/DIActorContextAdapter.cs#L27

New() should not be a constraint

[jcwrequests]

@rogeralsing @nvivo I will take care if this will 833. Thanks

[jcwrequests]

@Danthar @nvivo Please verify that PR#835 resolves this issue. Thanks.

[Aaronontheweb]

Resolved per #835