Added some javadocs that explains why the spellchecker does not work as one might expect it to.
> Without having looked at the code for a long time, I think the problem is what the
> lucene scoring consider to be best. First the grams are searched, resulting in a number
> of hits. Then the edit-distance is calculated on each hit. "Genetics" is appearently the
> third most similar hit according to Lucene, but the best according to Levenshtein.
> I.e. Lucene does not use edit-distance as similarity. You need to get a bunch of best hits
> in order to find the one with the smallest edit-distance.
I took a look at the code, and my assessment seems to be right.