author identification should be conservative

[Aaron Swartz]

Right now if two books list the same name as the author, they're listed as written by the same author ID unless manually split. The default should be the opposite: they should each get their own author ID, which can then be manually merged.

Why? Because the current interface shows wrong data, while the alternative never would. If an author is later split, links to the old author could break, whereas if authors are merged, links will redirect.