------------------
- Added :attr:`Field.connection`.
- Added ``app``.
- Added :class`NCPError`, :class:`ConnectionError` and :class`ConnectionClosed` exceptions.
- Added ``run_client``.
- :func:`connect`, :meth:`Connection.recv`, :meth:`Connection.recv_field`, :meth:`Response.recv` and
:meth:`Response.recv_field` no longer raise :class:`EOFError` or :class:`OSError`, but a subclass of
:class:`NCPError`.
- Micro-optimizations, roughly doubling the performance of encode/decode.
- Connection open and close log messages promoted from ``DEBUG`` to ``INFO`` level.