Added CNPJ and CPF validation formats

[LuanP]

Changed the re.sub to avoid cleaning CNPJ and CPF numbers sent in the wrong format.

Removed errors_numbersonly since the regex will take care of validating and raising a ValidationError with the error_format message.

If the message of errors_numbersonly error must be kept, just let me know.

[LuanP]

I'd like to bring the validations out of the clean method. Allowing users to use the validation functions directly. Could I do that?

Thanks

[claudep]

When reading the test updates, it's not obvious for me what you are trying to solve with this patch. If the only result is to have a different error message, it's not worth it I think. If your changes allow to catch more errors, please reflect that in the tests also.

[LuanP]

I've added a CNPJ number to the tests:
https://github.com/LuanP/django-localflavor/blob/change_cpf_and_cnpj_regexp/tests/test_br.py#L34

This PR makes that invalid.

[claudep]

Good, a similar test for CPF would be nice.

[LuanP]

@claudep oh... thanks, I forgot that. u.u

Added in
https://github.com/LuanP/django-localflavor/blob/change_cpf_and_cnpj_regexp/tests/test_br.py#L54

[LuanP]

@claudep Do you have any ideas about what happened with the builds py27-master and py34-master that raised an AssertionError in the Chilean RUT? Every other env has passed successfully.

Anything else I should do?

I'll create another PR to add validation formats to the BRProcessoField too and add tests to it, if that's ok.

Thanks.

[claudep]

I'm investigating the issue about test failures. But it's unrelated to this patch, that's why I merged it.

[LuanP]

Awesome! Thanks.