refactor IEventProvider: use property instead of getter method
refactor: Person.getLastname() to Person.Lastname property
Person: remove unnecessary sibling attributes
add by-name index to Reign
add ToString(int year) overload to Reign
add Reign references to Person
Person: override ToString(), provide ToString(int year) overload
refactor: Title.RuledTerritory ~> Title.Realm
more inspector windows
refactor title <-> country relation

Replace Country by Realm, which can be split into further Fiefdoms.
For each realm, specify the ruler, so one Title can belong to multiple
realms.
fix multiple strategies
formatting changes
remove superfluous field
add new ranks
TestApp: output some statistical data
extend test data
inspector: add double click actions on person's titles and children
minor refactorings