Spead2

- autotools are no longer required to install the C++ build (when installing
from a release tarball).

- Make :py:meth:`spead2.recv.asyncio.Stream.get` always yield to the event loop
even if there is a heap ready.
- Avoid :py:meth:`spead2.recv.asyncio.Stream.get` holding onto a reference to
the heap (via a future) for longer than necessary.

- Add support for TCP/IP (contributed by Rodrigo Tobar).
- Changed command-line options for
:program:`spead2_send`/:program:`spead2_recv`: :option:`!--ibv` and
:option:`!--netmap` are now boolean flags, and the interface address is set
with :option:`!--bind`.
- Added option to specify interface address for
:cpp:class:`spead2::send::udp_stream` even when not using the multicast
constructors.
- Constructors that take an existing socket now expect the user to set all
socket options. The old versions that take a socket buffer size are
deprecated. Note that the behaviour of :cpp:class:`spead2::send::udp_stream`
with a socket has **changed**: if no buffer size is given, it is left at the
OS default, rather than applying the spead2 default.
- Fix a bug causing undefined behaviour if a send class is destroyed while
there is still data in flight.

- Add :doc:`py-inproc`
- Fix unit testing on Python 3.7
- Add :cpp:func:`spead2::send::heap::get_item`
- Support asynchronous iterator protocol for
:py:class:`spead2.recv.asyncio.Stream` (in Python 3.5+).

- Add progress reports to mcdump
- Add ability to pass ``-`` as filename to mcdump to skip file writing.
- Add :option:`!--count` option to mcdump

There are no code changes, but this release fixes a packaging error in 1.7.0
that prevented the asyncio integration from being included.