Sqlalchemy-things

--------------
**Added**

* Handling ``number`` < 1 for ``pagination.OffsetPaginator.get_page_async()``
and ``pagination.OffsetPaginator.get_page_sync``.

**Changed**

* renamed ``page_number`` to ``number`` for ``pagination`` classes;
* renamed ``total_items`` to ``total`` for ``pagination`` classes.

-------------
**Changed**

* ``ValueError`` exception replaced with return ``None`` when exceeding
the ``max_page`` in ``pagination.OffsetPage``.

-------------
**Added**

* ``pagination.OffsetPage``.

**Changed**

* Renamed ``prepare_page_async()`` method to ``get_page_async()``
in ``pagination.OffsetPaginator``;
* Renamed ``prepare_page_sync()`` method to ``get_page_sync()``
in ``pagination.OffsetPaginator``.

**Removed**

* ``get_items()`` method from ``pagination.OffsetPaginator``;
* ``get_last_page_number()`` method from ``pagination.OffsetPaginator``;
* ``get_next_page_number()`` method from ``pagination.OffsetPaginator``;
* ``get_previous_page_number()`` method from ``pagination.OffsetPaginator``.

-------------
**Added**

* ``get_items()`` method for ``pagination.OffsetPaginator``;
* ``get_last_page_number()`` method for ``pagination.OffsetPaginator``;
* ``get_next_page_number()`` method for ``pagination.OffsetPaginator``;
* ``get_previous_page_number()`` method for ``pagination.OffsetPaginator``.

**Changed**

* Renamed ``get_page_async`` method to ``prepare_page_async``
in ``pagination.OffsetPaginator``;
* Renamed ``get_page_sync`` method to ``prepare_page_sync``
in ``pagination.OffsetPaginator``.

**Removed**

* ``pagination.OffsetPage``.

-------------
**Added**

* ``max_page`` attribute for ``pagination.OffsetPaginator``.

**Changed**

* Renamed ``next`` attribute to ``next_number`` in ``pagination.OffsetPage``;
* Renamed ``previous`` attribute to ``previous_number``
in ``pagination.OffsetPage``;
* Renamed ``limit`` attribute to ``page_size``
in ``pagination.OffsetPaginator``.

-------------
**Changed**

* Renamed ``pagination.CountOffsetPage`` to ``pagination.OffsetPage``;
* Renamed ``pagination.CountOffsetPaginator`` to ``pagination.OffsetPaginator``;
* Renamed ``get_async`` method to ``get_page_async``
in ``pagination.OffsetPaginator``;
* Renamed ``get_sync`` method to ``get_page_sync``
in ``pagination.OffsetPaginator``.