give the index updater threads a name of their own
read number of terms used for indexing from config, too
no longer needed
savepoint while trying to make stemmers exchangeable more easily

- add facade class for the "find concepts in text" analyser as OntologyConceptAnalyze
- add helper to create a GermanLightStemmer
- add config "ontoloy.use.lightstemmer" to switch between stemmers
- everywhere in OntoloyIndex made currenty unides methios private
  and annotate where they expect stemmed or orignal input
- also happened to update the getSimilarMatches(String, int)
  to make it more similar to the getSimilarMatches(String)