Extract flight number from either telemetry or eeprom files and use
that in the resulting filenames. To ensure that files remain unique,
add a new field, -seq-%03d. This is appended only when the sequence
number is non-zero as it shouldn't occur in normal usage.
This also eliminates some duplicate filename creation code in the
library and aoview sources.
Signed-off-by: Keith Packard <keithp@keithp.com>