Per Github issue #1704, N3FJP logger sends a string with an embedded
comma for frequencies above 1 GHz resulting in such frequencies being
truncated. This patch uses the optional apostrophe character in the
sscanf() format string to ignore the thousands separator.
A possible bug is when the locale of the system on which libhamlib is
executing uses a dot for the thousands separator rather than a comma.
It is unclear if the N3FJP software obeys such locales or not. If this
turns out to be an issue then this fix will need to be reconsidered.