fts: When searching data headers, don't expand search keys to all languages. For example "SEARCH HEADER Message-Id foo@example.com" works better the less expansion there is for "foo@example.com".

fts: Added support for per-language tokenizer settings. fts_tokenizer_<lang> now overrides fts_tokenizers setting. fts_tokenizer_<name>_<lang> now overrides fts_tokenizer_<name> setting.

fts: Lowecase non-human language input while indexing.

fts: Create tokenizers differently Create tokenizers earlier. Create separate tokenizers for search and indexing. Enable configuration of tokenizers. Add some helpers in fts-tokenizer.h api. Change tokenizer unit tests to match those changes. lib-fts: Refactor lib-fts settings a bit Turned address tokenizer settings into "boolean" values. Changed have_parent to "no_parent" and added "search" setting. Added documentation in fts-tokenizer.h. Change unit tests accordingly.

fts: Create filters earlier This builds on the assumption that early initialization will be made less costly, in a coming change.

fts: Fixed infinite looping at deinit. fts_mail_user_deinit() was calling itself. Now the fts backend is responsible for calling it at deinit.

fts: Don't always try to initialize lib-fts. Require backend to explictly do it now.

fts: Added FTS_BACKEND_FLAG_TOKENIZED_INPUT, which is implemented via lib-fts.