We no longer need the remove infrastructure, and the edit nickname function
becomes much more intuitive to use by passing in the dive computer for
which we want to create a nickname instead of the internal index into
the array of devices.
This also removes / simplifies the device list update signals in the
DiveListNotifier.
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add commands for deleting devices and editing device nicknames
to include the device-handling in the undo system.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>