the links between all pages are now stored. The same index structure as
used for the word index is used to make a reverse link index.
The new file(s) in SEGMENT/default/citation.index.*.blob store the
citation index. This will be used to create much more detailed link
structures for the YaCy apis and to create a better ranking. A ranking
using the citation.index should provide better results especially for
portal indexes and initranets.