add "introduction by" creator type to book item type

[erazlogo]

You can decide if this needs to be included in the citation but there are definitely cases when it's important to know who wrote the introduction for a given book.

​http://forums.zotero.org/discussion/917/introduction-by/#Item_5

[dstillman]

No more schema changes in 1.0.

[erazlogo]

Also need to refine citation for an introduction/afterword by one author to a book by another. This will require a special creator type--"Book Author" or something like that--in addition to "Author" (the author of the introduction/afterword). See discussion in the same forum.

[erazlogo]

moved "book author" to #872 since it's necessary while "introduction by" is a minor enhancement.

[stakats]

Perhaps better handled by #395.

[erazlogo]

Sean--yes #395 applies to "book author" (#872), but not to this--"intro by" is meant to be an attribute of a book item so there would be no hierarchical relationship:

Derrida, Jacques. Of Grammatology. Introduction by Gayatri Chakravorty Spivak. Baltimore and London: Johns Hopkins University Press, 1974.

i.e. I shouldn't have to create a book section intro item to record or cite this, just the book item.

[dstillman]

Elena: So should a (temporary or otherwise) introductionBy creator type be added (now) in addition to bookAuthor?

How would this be mapped to CSL?

[erazlogo]

It would be nice to have as an option in the db, although there is no analogous variable in CSL, so this would need to be discussed and added on xbiblio before implementing in citations.

[dstillman]

Going to hold off on this until there's CSL support, then.