Add Brazilian postcode (brCep)

[marcio]

Hi,

It's a simple validate for Brazilian postcode.

[arasatasaygin]

Hey @marcio It looks pretty good. I'm keeping this PR because I still did not decide if we should add these methods to library or provide a method to the library user to set new RegExps on the fly.
What do you think about it?

[davidhund]

@arasatasaygin while you think about that you could add a NL postalcode regex :-)
/^[1-9][0-9]{3}\s?[a-zA-Z]{2}$/

[marcio]

Hi @arasatasaygin!
Provide a method for the user to set new RegExps sounds very nice. I think this is more elegant way to is.js be customizable and powerful. Maybe something like lodash mixins approach https://lodash.com/docs#mixin. (https://github.com/lodash/lodash/blob/master/lodash.js#L10054).

It's your turn, what do you think about it? 😃

[arasatasaygin]

Hey @marcio like you said, providing a method for the user is more elegant and will prevent long run bloats. You can check #15 if you are interested.
Thank you very much.