index app should support complex names

[NTsch]

The index does not currently contain files with XML annotation beyond the level of tei:persName, and therefore the creation of the display frame for the named entry only looks at the immediate text within the tei:persName element. If the data beyond this element is also modeled (e.g. with name, roleName, etc. - this is the case in the Fontenay index), this causes errors.