[teqc] teqc RINEX header editing

[Lou Estey]

 > [...] E.g. the header.cfg contained the option `-rds` = reverse
> doppler sign should not be used unless you are absolutely certain that
> the input doppler sign is reversed; [...]

Apologies to Roberto about this one.  It turns out that the printing
of the header comment line with `-rds` = "don't reverse Doppler signs":

SIGN OF DOPPLER BEING REVERSED                              COMMENT

was a bug.  That line should only have been printed with `+rds` =
"reverse Doppler signs".  (Roberto's config file had `-rds`.)
Just to be clear, this was just a comment error; _only_ using `+rds`
will actually switch the sign of the D1 and/or D2 Doppler values in
the data.  This comment error has been fixed in the current development
version of teqc.

Sorry about that.

cheers,
--lou