stbt.py: Corrections according to Dave's review comments (fixup)

See https://github.com/drothlis/stb-tester/commit/fa6c0d9.
stbt.py: `stbt record` to receive keypresses via a lirc TCP socket (fixup)

Testing multiple lirc devices, I had the experience that using a lirc
file socket as 'control_recorder' and a TCP socket as 'control' at the
same time is not straightforward. First I couldn't make it work, then
after playing with the configuration for a while it started working but
I couldn't recall the step that was the key to make it work.

On the other hand, listening on a TCP socket and sending to another TCP
socket is working fine and it's easy to configure, therefore I find it
better to modify stbt to be able to record keypresses from a TCP port
than spending hours with LIRC configuration. Also, it makes lirc
implementation in stbt more complete and allows to record from a lirc
device connected to a remote server.