Last gas used will be used on new dive planner point.

This patch makes the last gas used on the planner the
default.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Make the Plus Button on the planner work.

Clicking on the plus button now adds a new stop on the planner.
The depth is always 10m and the time is 10 minutes after the
last stop. can be changed by double clicking or dragging the
balls around the canvas.

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