If no average depth is known the current fake profile behavior is rather
unintuitive (we make up an average depth).
Instead we should assume that this is a PADI style dive log and give the
user a "rectangular" profile (actually, it's a trapecoid as we at least
try to enforce a sane ascent / descent speed). If the dive is somewhat
longer or deeper (10 min / 10 m) we even add a 3m safety stop at 5m.
Added a new dives/test0b that tries to capture the typical cases to test
this.
Fixes#398
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
