Rename the kindex_extractor macro to kzip_extractor. (#3073)
Rename the kindex_extractor macro to kzip_extractor. (#3073)

Also update some doc string text that needed updated anyway.
kythe/kythe,kythe/kythe,bzz/kythe,bzz/kythe,bzz/kythe,kythe/kythe,bzz/kythe,bzz/kythe,kythe/kythe,kythe/kythe,bzz/kythe,kythe/kythe,bzz/kythe,kythe/kythe,bzz/kythe,bzz/kythe,kythe/kythe,kythe/kythe,bzz/kythe,kythe/kythe,bzz/kythe,kythe/kythe,bzz/kythe