Add Z seam view

[synsuiter]

Is your feature request related to a problem? Please describe.
Unable to view where the Z seam is placed in the Layer view of a slice. Not a problem, but would be a very helpful feature.

Describe the solution you'd like
The layers appear as lines, so could we add a "dot" or a different colored line segment or something to signify the area of the Z scare placement?

Describe alternatives you've considered
This is a feature request, no alternatives that I can think of.

Additional context
Not even sure if this is possible with our SympleSlicer setup, let me know.