Fix ISBN-10 to ISBN-13 conversion.
Fix ISBN-10 to ISBN-13 conversion.

bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode,bwipp/postscriptbarcode