Added the possibility to change the coordinates of a dive.

Added the possibility to change the coordinates of a dive.
it's too intrusive in the moment, but it was a proof
of concept. so I'll commit as is and try to find a better
way to warn the user what's going on in the future, using
something less terrible than a popup exploding in his face.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>