I have made one change to `gcode.py` to support quoted parameter
values.
I have added support for the basic `M118` command (see
https://reprap.org/wiki/G-code#M118:_Echo_message_on_host). I have
also added a `RESPOND` command that takes extended parameters.
`ECHO` might be a better name than `RESPOND` but is already defined
in `gcode.py`.
Signed-off-by: Alec B. Plumb <alec@etherwalker.com>
Alec B. Plumb