Fix issue #535 and add test cases

[dhAlcojor]

This time I edited the right file (^^U) and added some test cases for Union Pay credit cards.

This fixes #535.

[coveralls]

Coverage remained the same at 99.091% when pulling 7153ce7 on dhAlcojor:master into 3c9b751 on chriso:master.

[chriso]

/^62[0-9]{5,}$/ would allow through something like 6212345 which doesn't look valid. Where did you get this regex from?

A few other places validate as follows:

• /^62[0-5]\d{13,16}$/ from http://www.richardsramblings.com/regex/credit-card-numbers/
• /^(62[0-9]{14,17})$/ from http://stackoverflow.com/questions/9315647/regex-credit-card-number-tests

Can you fix the regex?

[dhAlcojor]

In this document (https://www.six-payment-services.com/dam/downloads/datasheets/110004302_DS_SecurityFeatures_UnionPay_INT_EN_opt.pdf) it says that Union Pay credit cards start with a 62 and have 16 digits.

But it's not clear (to me, at least), what happens with Union Pay debit cards because it says that they have 13 - 19 digits and that some debit cards can start with 3, 4, 5 or 9. This sounds a little crazy, so I'll implement the regex for Union Pay credit cards.

[chriso]

/^(62[0-9]{14})$/ should be fine for now.

[chriso]

The test failure appears unrelated.

[dhAlcojor]

Yeah, my edit didn't seem capable of breaking anything...