Bibliography alpha sorting by case

[stakats]

Exported bibs currently sort by case, leaving de Frenchie and van Dutchie at the end of the list. These entries need to be mixed in with the rest. To avoid any kind of complicated locale-based name sorting logic, let's just put them in plain old alphabetical order. Note that this problem is distinct from #376.

[dstillman]

This will probably be fixed by fixing #376, though, since ZoteroPane.getSortedItems() should do it right (assuming the items pane order is correct).

(If a raw SQL query, it would need COLLATE NOCASE at the end (though we should probably change the default collation of various columns in the database and stop putting COLLATE NOCASE everywhere)).

[simon]

(In [1118]) closes #505, Bibliography alpha sorting by case
closes #376, Bibliography export order jumbled
closes #482, Tag selector does not refresh on import/delete
closes #499, zotero RDF import of attachments has a flaw
closes #500, Improve COinS handling of other item types

• fixes an issue with importing directory hierarchy
• fixes an issue where the SpringerLink translator could fail to recognize a scrapable resource
• fixes an issue where the Nature translator could fail to retrieve an associated PDF

feel free to push the updates to the SpringerLink and Nature translators to the repository; theoretically, the RDF translator should be backwards-compatible too, but I'd like to test it with b3 before potentially breaking functionality.