Question about duplicate schema references in linkedCategory handling

[lzehl]

Categories help us to group schemas together that are frequently linked in various edges.
Of course schemas could in principle belong to multiple categories.
Now what happens if under linkedCategory two categories are linked which have overlapping schemas items?

I think for using the full power of categories we should be able to deal with this (creating in the build the set of both categories), but I'm not sure we were already that smart (@Raphael-Gazzotti could you check the code?).

@olinux @apdavison Would you agree?

[Raphael-Gazzotti]

'_linkedCategories' and '_embeddedCategories' just add to '_linkedTypes' and '_embeddedTypes', respectively. I didn't notice handling of items/properties based on them.