Stop cluttering stout with DC_VENDOR data

This was intended for debugging and somehow stayed enabled.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Remember serial and firmware for divecomputers

This is not the right way to get serial numbers and firmware versions. The
libdivecomputer interface here is simply broken. Those ARE NOT numbers.

But until we have the capability in libdivecomputer to return reasonable
strings to us, this could be a stop gap measure to help us understand how
these are formatted.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>