Timeouts / Convert inbound activities to proactive

[cleemullins]

[@stevenic] We should really consider adding an option to the adapter which essentially turns every inbound request into a proactive message. Customers keep getting tripped up on long running operations. I know @benbrown has had a lot of complaints on the BotKit side as well.

[EricDahlvang]

@cleemullins a dotnet immediate-accept-adapter will be in experimental once R10Samples are merged: https://github.com/microsoft/BotBuilder-Samples/tree/R10Samples/experimental/immediate-accept-adapter/csharp_dotnetcore

Here is an attempt at a typescript one. Unfortunately, i'm not sure how to postpone shutdown ... so it isn't super useful imo: immediate-accept-adapter-typescript_nodejs2.zip