Add Go benchmark

[mavam]

Go qualifies as another benchmark candidate: Goroutines are the equivalent of actors. They become non-blocking when used with buffered channels (though only until the buffer is full). Pattern matching occurs with the switch statement on a value read from a channel:

val := <- someChannel
switch val.(type) {
      case int: // some code
      case float32: // some code
}

[ivaxer]

Related: https://github.com/Neverlord/cppa-benchmarks/pull/5