Support better gRPC error handling

[Msirkovsky]

I have a problem with empty error:
I call:

 client.getAllMetadata({}, pr)

and I recevied empty error:

 Error:  { Error
    at C:\user\AppData\Roaming\npm\node_modules\grpcc\node_modules\grpc\src\node\src\client.js:554:15 code: 12, metadata: Metadata { _internal_repr: {} } }

Is the error from gRPC endpoint or grpcc tool? Thank you.

[Msirkovsky]

the error was at grpc endpoint. It returned status Unimplemented with no details.
It will be great if this status will be shown in grpcc tool too.

[njpatel]

Yeah, i want to support grpc errors soon, so we can detect and print them in a nicer fashion. I'll keep this bug as a tracker for that. Thanks.