* New: In AutoSegment::getExtensionCap(), when a routing layer has a
minimal area defined, compute the minimal wire length (given it's
width). Then, for segments identified as "MiddleStack" (local
with turns at each end towards opposite layers), if their length
is below minimal, return a longer extention cap.
This may be optimized because with this, the segment extension
is symmetric on both side while it could be made assymetric.