WordListLoader is basically used for loading up stopwords lists, stem dictionaries, etc.
Unfortunately the api returns Set<String> and sometimes even HashSet<String> or HashMap<String,String>
I think we should break it and return CharArraySets and CharArrayMaps (but leave the return value as generic Set,Map).
If someone objects to breaking it in 3.1, then we can do this only in 4.0, but i think it would be good to fix it both places.
The reason is that if someone does new FooAnalyzer() a lot (probably not uncommon) i think its doing a bunch of useless copying.
I think we should slap @lucene.internal on this API too, since thats mostly how its being used.