Serial console

work in progress - I'm finding failure modes that I hope to debug first
Relying on Sleep for another goroutine to complete may not be very portable.
Instead, maybe:
```go
ch := make(chan bool)
go reader(c, ch)
<- ch
```
and the reader will close the channel when it is done.  Or you could use a select for a timeout... or you could just leave it as is.  :-)