Ngrams table is ok: new menufilter for maplist + fix pagination bug + strikethrough for stoplist + css

FIX unrecognized languages at ngrams extraction were stopping downstream process like stemming: now metadata allows to continue skipping document in further processes

table js: simplify access to records taking advantage of new structure where record id became the same as ngram_id (see commit 39b176f9 compared to file before refactoring)