ISuccessionStrategy: add Title property
IPreferenceFilter: add Title parameter to methods

As a result of this, IPreferenceFilters can no longer implement
IComparer<Person> directly. To solve this, add a private class
AbstractSuccessionStrategy.PreferenceFilterComparer that, given
an IPreferenceFilter and a Title, implements IComparer<Person>
by delegating calls to the IPreferenceFilter.
add new PorphyrogeniturePreferenceFilter