Tortoise-orm

-----
- ``JSONField`` is now promoted to a standard field.
- Fixed ``DecimalField`` and ``BooleanField`` to work as expected on SQLite.
- Added ``FloatField``.
- Minimum supported version of PostgreSQL is 9.4
- Added ``.get(...)`` shortcut on query set.
- ``values()`` and ``values_list()`` now converts field values to python types

-----
- Fixed ``through`` parameter honouring for ``ManyToManyField``

===========

-----
* Added support for nested queries for ``values`` and ``values_list``:

.. code-block:: python3

result = await Event.filter(id=event.id).values('id', 'name', tournament='tournament__name')
result = await Event.filter(id=event.id).values_list('id', 'participants__name')

- Fixed ``DatetimeField`` and ``DateField`` to work as expected on SQLite.
- Added ``PyLint`` plugin.
- Added test class to mange DB state for testing isolation.

-----
- Added PostgreSQL ``JSONField``

-----
- Added ``.annotate()`` method and basic aggregation funcs