py-tox: updated to 3.0.0

3.0.0:
Bugfixes
Write directly to stdout buffer if possible to prevent str vs bytes issues
fix 672 reporting to json file when skip-missing-interpreters option is used
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
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
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.
(only affected rc releases) fix up tox.cmdline to be callable without args
(only affected rc releases) Revert breaking change of tox.cmdline not callable with no args
(only affected rc releases) fix 755 by reverting the cmdline import to the old location and changing the entry point instead

Features
tox displays exit code together with InvocationError
Hint for possible signal upon InvocationError, on posix systems
Add a -q option to progressively silence tox窶冱 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
add support for negated factor conditions, e.g. !dev: production_log
Headings like installed: <packages> will not be printed if there is no output to display after the :, unless verbosity is set. By @cryvate
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
drop Python 2.6 and 3.3 support: setuptools dropped supporting these, and as we depend on it we窶冤l follow up with doing the same (use tox <= 2.9.1 if you still need this support)
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
Forward PROCESSOR_ARCHITECTURE by default on Windows to fix platform.machine().


(adam)