File Release Notes and Changelog

This is the first steps with libtextcat. 

On my laptop it seems a bit long (17ms/query) 
and 89% real good, 10% with too much guessed lang 
(more than one), and less than a percent too SHORT 
or UNKNOWN (My datatest is only french and short 
sentences).

Thanks Dalibo for worktime sponsor.

* Initial commit
* return the guessed lang(s) (need libtextcat)
* no options, draft code