Faker

* Fix missing and misplaced comma's in many providers. Thanks 153957.
* Refactor IPv4 address generation to leverage ``ipaddress`` module.
Thanks maticomp.
* An ``en_NZ`` provider for addresses, phone numbers and email addresses.
Thanks doctorlard.
* Add ``unique`` argument to ``words()`` for returning unique words.
Thanks micahstrube.
* Allow US territories to be excluded from ``state_abbr()`` for ``en_US``
provider. Thanks micahstrube.
* Add support for Python 3.7. Thanks michael-k.

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* ``.random_sample()`` now returns a list of unique elements instead of a set.
* ``.random_sample_unique()`` is removed in favor of ``.random_sample()``.
* Added ``random_choices()``, ``random_elements()`` and ``random_letters()``.
* Added ``faker.utils.distribution.choices_distribution_unique()``.
* ``words()``, ``password()``, ``uri_path`` and ``pystr()`` now use the new the
``random_choices()`` method.

* Change blood group from ``0`` (zero) to ``O`` (capital letter O). Some
locales do use 'zero', but ``O`` is more common and it is the medical
standard. Thanks mohi7solanki.
* Fix alpha-2 country code for Haiti. Thanks sevens-ef for the report.
* Fix abbreviation for Nunavut. Thanks straz for the report.
* Standardized ``postcode`` in address providers. Now all locales are
guaranteed to have a ``postcode`` method and may have a localized alias for
it (eg: ``zipcode``). Thanks straz for the report.
* Fix typo in ``pt_BR`` Person perovider. Thanks Nichlas.
* Fix timezone handling. Thanks Fraterius.
* Use tzinfo when provided in ``date_of_birth``. Thanks Kelledin.

* Add ``ein``, ``itin`` and refactored ``ssn`` Provider for ``en_US``.
Thanks crd.
* Add ``job`` provider for ``zh_CN``. Thanks ramwin.
* Add ``date_of_birth`` provider. Thanks cdr.
* Add alpha-3 representation option for ``country-code`` provider. Thanks cdr.

* Fix test for CPF (Brazilian SSN). Thanks Rubens Takiguti Ribeiro.
* Fix Canadian SIN generation. Thanks crd.
* Fix Norwegian SSN date portion. Thanks frangiz.
* Add ``start_datetime`` argument for ``unix_time()``. Thanks crd.

* Change logging level to ``DEBUG``.