First implementation of format()

Better to use `new Date(2014, 8, 2)` because in some cases tests may fail because of time zone difference:

``` javascript
new Date('2014-09-02T11:55:00').toISOString();
//=> '2014-09-02T11:55:00.000Z'
new Date(2014, 8, 2, 11, 55, 0).toISOString();
//=> '2014-09-02T07:55:00.000Z'
```

In this particular case it doesn't matter, but better to keep consistency for new code.