Update tox to 3.0.0

[pyup-bot]

This PR updates tox from 2.9.1 to 3.0.0.

Changelog

3.0.0rc2

---------------------

Bugfixes
^^^^^^^^

- fix 755 by reverting the ``cmdline`` import to the old location and changing
the entry point instead - by fschulze (`755
<https://github.com/tox-dev/tox/issues/755>`_)


Features
^^^^^^^^

- ``tox`` displays exit code together with ``InvocationError`` - by blueyed
and ederag. (`290 <https://github.com/tox-dev/tox/issues/290>`_)
- Hint for possible signal upon ``InvocationError``, on posix systems - by
ederag and asottile. (`766 <https://github.com/tox-dev/tox/issues/766>`_)


Documentation improvements
^^^^^^^^^^^^^^^^^^^^^^^^^^

- Change favicon to the vector beach ball - by hazalozturk (`748
<https://github.com/tox-dev/tox/issues/748>`_)

3.0.0rc1

---------------------

Bugfixes
^^^^^^^^

- Write directly to stdout buffer if possible to prevent str vs bytes issues -
by asottile (`426 <https://github.com/tox-dev/tox/issues/426>`_)
- fix 672 reporting to json file when skip-missing-interpreters option is used
- by r2dan (`672 <https://github.com/tox-dev/tox/issues/672>`_)
- avoid ``Requested Python version (X.Y) not installed`` stderr output when a
Python environment is looked up using the ``py`` Python launcher on Windows
and the environment is not found installed on the system - by
jurko-gospodnetic (`692 <https://github.com/tox-dev/tox/issues/692>`_)
- Fixed an issue where invocation of Tox from the Python package, where
invocation errors (failed actions) occur results in a change in the
sys.stdout stream encoding in Python 3.x. New behaviour is that sys.stdout is
reset back to its original encoding after invocation errors - by tonybaloney
(`723 <https://github.com/tox-dev/tox/issues/723>`_)
- The reading of command output sometimes failed with ``IOError: [Errno 0]
Error`` on Windows, this was fixed by using a simpler method to update the
read buffers. - by fschulze (`727
<https://github.com/tox-dev/tox/issues/727>`_)


Features
^^^^^^^^

- Add a ``-q`` option to progressively silence tox's output. For each time you
specify ``-q`` to tox, the output provided by tox reduces. This option allows
you to see only your command output without the default verbosity of what tox
is doing. This also counter-acts usage of ``-v``. For example, running ``tox
-v -q ...`` will provide you with the default verbosity. ``tox -vv -q`` is
equivalent to ``tox -v``. By sigmavirus24 (`256
<https://github.com/tox-dev/tox/issues/256>`_)
- add support for negated factor conditions, e.g. ``!dev: production_log`` - by
jurko-gospodnetic (`292 <https://github.com/tox-dev/tox/issues/292>`_)
- Headings like ``installed: <packages>`` will not be printed if there is no
output to display after the :, unless verbosity is set. By cryvate (`601
<https://github.com/tox-dev/tox/issues/601>`_)
- Allow spaces in command line options to pip in deps. Where previously only
``deps=-rreq.txt`` and ``deps=--requirement=req.txt`` worked, now also
``deps=-r req.txt`` and ``deps=--requirement req.txt`` work - by cryvate
(`668 <https://github.com/tox-dev/tox/issues/668>`_)
- drop Python ``2.6`` and ``3.3`` support: ``setuptools`` dropped supporting
these, and as we depend on it we'll follow up with doing the same (use ``tox
<= 2.9.1`` if you still need this support) - by gaborbernat (`679
<https://github.com/tox-dev/tox/issues/679>`_)
- Add tox_runenvreport as a possible plugin, allowing the overriding of the
default behaviour to execute a command to get the installed packages within a
virtual environment - by tonybaloney (`725
<https://github.com/tox-dev/tox/issues/725>`_)
- Forward ``PROCESSOR_ARCHITECTURE`` by default on Windows to fix
``platform.machine()``. (`740 <https://github.com/tox-dev/tox/issues/740>`_)


Documentation improvements
^^^^^^^^^^^^^^^^^^^^^^^^^^

- Change sphinx theme to alabaster and add logo/favicon - by hazalozturk
(`639 <https://github.com/tox-dev/tox/issues/639>`_)


Miscellaneous / trivial changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

- Running ``tox`` without a ``setup.py`` now has a more friendly error message
and gives troubleshooting suggestions - by Volcyy. (`331
<https://github.com/tox-dev/tox/issues/331>`_)
- Fix pycodestyle (formerly pep8) errors E741 (ambiguous variable names, in
this case, 'l's) and remove ignore of this error in tox.ini - by cryvate
(`663 <https://github.com/tox-dev/tox/issues/663>`_)
- touched up ``interpreters.py`` code and added some missing tests for it - by
jurko-gospodnetic (`708 <https://github.com/tox-dev/tox/issues/708>`_)
- The ``PYTHONDONTWRITEBYTECODE`` environment variable is no longer unset - by
stephenfin. (`744 <https://github.com/tox-dev/tox/issues/744>`_)

Links

• PyPI: https://pypi.python.org/pypi/tox
• Changelog: https://pyup.io/changelogs/tox/
• Docs: https://tox.readthedocs.org/

[coveralls]

Coverage remained the same at 85.821% when pulling 0dde39d on pyup-update-tox-2.9.1-to-3.0.0 into 6392343 on master.

[pyup-bot]

Closing this in favor of #63