Also, (length allDocs) queries were replaced by proper count queries
from the DB which is more efficient, except for the table query (this is
a bit more complex).

[API/DB] Fav AND Delete in NodeNode => category as Int wher 0 = Deleted, 1 or null = Neutral, 2 = Favorite.

[Ngrams Table] Front and Back implemented (but need next step for optimization and behavior of group controls (multichild issue)).