Whitelist barcode fonts

[davelab6]

Per graphicore/librebarcode#3

[felipesanches]

I'm starting to wonder whether we should maintain hardcoded whitelists within Fontbakery itself. It is starting to feel like a big hack. Perhaps the good way would be having whitelists on some sort of user config.

Then we can, off course maintain sample configs with the our own whitelists.

[felipesanches]

There's a bit of risk of over-engineering here, though. But I think it can get messy (and gradually messier) to keep adding hardcoded exceptions.

[davelab6]

We need the barcode exceptions fixed immediately.

We can clean it up later.

[felipesanches]

I can also quickly resolve this by fulfilling this Barcode whitelist request now and leaving this issue open for thinking of cleaner solutions later, off course :-)

[davelab6]

I filed a separate issue :)

[felipesanches]

thanks

[graphicore]

@felipesanches not sure if my CCing you in that comment was sent to you, because it was made in an update to that post: #1540 (comment)