[biblatex] Extended language support and several small enhancements

- (Almost) All babel languages can now be written to langid.
- Add getCollections : true for exporting collections recursively.
- Default to type = phdthesis if type field for a thesis is empty or contains "PhD" in any reasonable form.
- Handle special cases of bookSection -> inbook (for parts of a book which isn't a collection, i.e. has bookAuthor) and book -> collection (for books without authors but with editors).
- Some deprecated code was fixed
Merge pull request #674 from andersjohansson/biblatex-enhancements

Biblatex enhancements