config: reduced log level in example config and changed default path
fuzzy: get rid of fuzzy mutex, loading is thread-unsafe now, it should be handled on higher level
spell: switched to per-thread structures (or shards), containing word2lemma mapping

There are 2 levels: precise word2lemma map and fuzzy search against lemmas
Both return strcture containing multiple lemmas with so called frequencies.
The same word form can be formed from different lemmas hence multiple lemmas.
Frequency should be a metric of how frequent this word was found in the world texts,
so that fuzzy or direct search would not try to 'convert' given word into something rare.

But this logic should better use ngrams or sentencies to detect context, which should
help selecting between multiple lemmas for the same word form.

Returned structure also contains edit distance.