Many thanks for including hunspell support!
It does work as intended (and very quickly!) for en_US, but I am also having trouble while attempting to use additional dictionaries with the 64bit version, in my case, Bulgarian. I extracted the proper bg_BG.dic and bg_BG.aff to
bg_BG is available for selecting as a dictionary, but all Bulgarian words are underlined, even if spelled correctly, and there are no suggestions in the right-click menu. I guess that this is some kind of an encoding problem, but it will need to be ironed out.
I wonder if it would be possible to include some more traditional spelling functions in addition to the “spell-as-you-type” facility, for example, a traditional spell-check that goes through all unrecognised words and offers suggestions, as well as an option to accept a word for the current session.