Just read this today:
This Is How ‘Interstellar’’s Co-Writer Wanted the Movie to End
Unless I'm mistaken, the first ’ is the closing quote, and the second one the apostrophe... (and in OCR'd text, ’’ can also stand for mis-recognized closing double quotes when you have nested quotes...)
And, in headings or in verses, [a-zA-Z]’$ can be either an apostrophe or a closing quote...
I think that using the same symbol for apostrophes and closing quotes really hasn't been the best idea the British ever had.
I'm not an expert on Unicode and stay with Windows 1252 whenever I can, but even Unicode doesn't really help to clear up the mess, it seems:
http://www.unicode.org/L2/L2007/07241-mirroring.txt
So... a bit playing with regular expressions, and then we're back to good old proofreading/editing...