While it's nice to have immediate response to gradient factor changes,
there is an oddity that very low GFHigh values can cause infinite
decompression if the last stop is at 6m.
Robert fixed this and now errors out of deco after 48 hours, but if the
user simply wants to edit their GFHigh from (for example) 75 to 70 and
deletes the '5', we really don't want to trigger a recalculation for
GFHigh of 7...
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
