Complete rewrite of the type handling.
This means the addition of a new class to keduvocdocument: KEduVocWordType.
Word types are handled by getting a pointer KEduVocWordType* KEduVocDocument::wordTypes().

The class provides functions for adding types and subtypes and also has a special type QString to prevent users from deleting types necessary for certain query types (verb for conjugation etc.). These types can be renamed still.

Within KVocTrain a few type_relation and other curious functions go away. When this is done with usages as well, a few more interdependencies will go away.
To handle types in KVocTrain a new model and treeview has been added.

Note: next step is to adapt the old reader/writer. And move the compability maps and functions away from KEduVocWordType.

At document creation time a good preset (maybe the old types) should also be created.
Also the old typeDescription QStringList has to be removed.