ToolsRoundIn.OnDone - objectPointSav is never assigned to

[dsn27]

CS0469 - Field 'ToolsRoundIn.objectPointSav' is never assigned to, and will always have its default value

The code needs to fixed.

• Remove dependency on objectPointSave
• Assign value to objectPointSave
• Choose a different relevant point

https://github.com/FriendsOfCADability/CADability/blob/d8b0205bfef5c1bdafed78d2a4be047c3071ffc8/CADability/ToolsRoundIn.cs#L478-L494