Ignore ISBN value of 0123456789

[niavasha]

One of my books was matching this and giving erroneous results, so, quick fix and it works well.

[niavasha]

done

[na--]

Thanks for this! I remember facing a similar issue where several books had 1111111111 or something similar that was a valid ISBN. It was in the beginning of the books and totally broke the metadata fetching... So I like the idea of having some sort of ISBN blacklist, but I'd prefer a more generic and configurable solution.

I think that I'll add a new option for that ISBN blacklist. It will have a sensible default value (including 0123456789 and any ISBNS that contain only the same digit), but users would be able to override it with whatever they want.

[na--]

@niavasha, I think I implemented the generic version of this in a somewhat flexible way. Please take a look and see if you like it and if it works as expected.

Thanks for the idea and contribution! I'll close this for now, but feel free to reopen it or open a new PR or issue if you find any problems.