update credit card regex

fixes #1138

Update credit card regex.

Source: [stoackoverflow](http://stackoverflow.com/questions/72768/how-do-you-detect-credit-card-type-based-on-number). 
Others: [stackoverflow 2](http://stackoverflow.com/a/9315696/2256325), [web1](http://www.regular-expressions.info/creditcard.html), [web2](https://gist.github.com/nerdsrescueme/1237767), [stackoverflow 3](http://stackoverflow.com/a/1463289/2256325) - _all use same regex_.