There are two cases where dive-times are shifted: in an explicit
dialog and when editing the date/time of a dive.
In each of these cases, the selected dives were collected manually.
Instead use the getDiveSelection() function. Since this returns
a std::vector, change the argument of Command::ShiftTime() to
such a std::vector.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
c495a49b1b