Expand results through OCLC identifiers/API

[ryanfb]

For example (via @hadro in #8): http://babel.hathitrust.org/cgi/pt?id=mdp.39015085786880 shows OCLC http://www.worldcat.org/oclc/66269195 which has ebook versions http://www.worldcat.org/title/translation-of-the-confucian-i-ching-or-the-classic-of-change/oclc/220258848/editions?referer=di&editionsView=true#%2528x0%253Abook%2Bx4%253Adigital%2529format which associates back to HT and also to GB at: https://books.google.com/books?id=HJhKAQAAMAAJ + https://books.google.com/books?id=QAEaAQAAIAAJ

[ryanfb]

After implementing OCLC identifier search for #3, the example http://babel.hathitrust.org/cgi/pt?id=mdp.39015085786880 still doesn't get Google Books hits, so this isn't redundant with that functionality.