From the nmea specifications it is clear that the talker ID
does not have to start with 'G'. Accordingly remove ALL these
incorrect hardcoded checks against (a very small subset) of
known talker IDs, and permit any two-character string
as a valid talker ID
Fixes connection to NMEA devices which use "IN" for
talker ID (and others)
This is messy, as there's no way we can possibly make the current,
stable API of this class safe. We have to resort to an opt-in
"safe" mode which exposes a non-dangerous API.
This should hopefully fix issues where the qt event loop causes
destruction of the detected connection before listener slot is
called and is able to take ownership of the signal argument...
