Phyiscal Switch for Water

[lordfolken]

I'd love to add a reed switch for the water lever.

This would then trigger the drain process on xcsoar via xcvario protocol
and automatically decrease the ammount.

In xcsoar we could implement a warning that uses the ETA at the end of a task to notify the pilot to drain the tanks.

[iltis42]

At the moment there is not a free input once gear-warning and both serial interfaces are in use.