adding line condition

[inigolcanalejo]

Please do not approve because this does not work.

Right now the wake condition contains only the nodes of the trailing edge. I would like it also to contain the line conditions, but I don't know how to implement this in the interface. I have tried changing the lines indicated in this PR but it doesn't work. Do you know what am I missing?

What I am aiming for is to obtain the following lines in bold in the mdpa, which are currently not being written:

Begin Nodes
(nodes)
End Nodes
Begin Elements Element3D4N// GUI group identifier: Parts Auto1
(elements)
End Elements
Begin Conditions SurfaceCondition3D3N// GUI group identifier: HIDDEN__SKIN
(triangle conditions)
End Conditions

Begin Conditions LineCondition3D2N
17 0 2 7
End Conditions

Begin SubModelPart Wake3D_Wake_Auto1 // Group Wake Auto1 // Subtree Wake3D
Begin SubModelPartNodes
2
7
End SubModelPartNodes
Begin SubModelPartElements
End SubModelPartElements
Begin SubModelPartConditions
17
End SubModelPartConditions
End SubModelPart