Begin of a class KEduVocIdentifier.
So far it only contains name and locale.

From now on:
- locale = two letter language code, en, es, de,...
- name = description of the contents - English, Spanish, Famous people, Definition, Muscle in latin,...

Next will be to move the articles and personal pronouns into the identifier class.
Eventually the tenses should be kept there as well.

Adapted all readers/writers.
Appending identifiers should always give sane default values.