Add interfaces for ServerAsyncReader/Writers

Simplify compression interop

Remove AsyncStreaming client from python qps tests

Added python jwt_token_creds interop test

Fix sed induced typo

Enable use of pollset_set for a channel call

Let Next set ok=true when receiving error status

Make grpc++ independent of protobuf

Automatically capture transitive dependencies for Visual Studio solution files

Add more Channel and Server constructor overloads

C#: don't require Channel.ShutdownAsync() and Server.ShutdownAsync() to be able to exit.