From Master, commit 686254.
In some cases a created pad stack name had the same name as an other pad stack
having a slightly different shape, thus creating pads with a incorrect shape on board.
Fixes#6495 for the 5.1.10 branch.
* Specctra exported polygons are now closed (as required)
* export custom shape is provided in code, but not activated, because i have no way to text it
* fix Specctra export dialog (replace OK and Cancel buttons by only one Close button)