Finnish additions (personal identity number & iban account format)

Hi!

It would be nice if these could be added to the repository. 

Thanks, 
Jouni Mäkeläinen
I think that's a bad way of testing validity for each different case. Dependencies between tests is a bad practice IMO. You'd better create a private method for validity assertion, and call it in all test cases, e.g.:

```php
    public function testSafePIN()
    {
        $pin = $this->faker->safePersonalIdentityNumber();
        $this->assertEquals('9', substr($pin, 7, 1), "First character of the individual number isn't 9");
        $this->assertPinIsValid($pin);
    }
```