Add logging for all IO to/from peers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Put new_log into minimal log, add log_io.

Don't need to cut & paste dummy one into each test!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Per-JSON-RPC connection logging (and log IO)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fix jsonrpc reliability.

First, we weren't always closing the fds.

Secondly, we were sometimes stalling.

Thirdly, if we got two commands in a row we'd overwrite out output.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>