Fix the parsing of freedives.
Fix the parsing of freedives.

In freedive mode the sample rate is only 1 second instead of 4 seconds.
The tank pressure fields appear to be re-used for some other (unknown)
purposes, and should be ignored.

glance-/libdivecomputer,Poltsi/libdivecomputer-vms,henrik242/libdivecomputer,henrik242/libdivecomputer,glance-/libdivecomputer