improve usage
adding @since annotation
fix use of TestTools.getMessages()
test without reflection - needed to make method non-private for that, but we do that at several places and it still feels less ugly than using reflection
improve method order
[en] add more tests for good spell checker suggestions
add another mode: find ngrams contexts in which one of the words from a word set occurs much more often than the other (e.g. to create rules that detect 'their/there' confusion)