[TIP] Tox command line arguments (redux)

[Chris Rose]

I noticed from the archive that my original attempt to send this
truncated after my assertion that this was "obviously undesirable".

Not a well-supported assertion, clearly.

So, here's a second attempt to make the request, this time hopefully
it all ends up appearing.

=======
I ran into an issue with tox command positional argument substitution
that I was going to look into fixing, but it turns out that at least
to some extent the issue is by design (at least, according to the unit
tests in tox).

Here's my own example, with expected behaviour:

command = nosetests -m '(?:^|[\\b_\\./-])(?:unit)?[Tt]est'

Tox substitutes this as:

nosetests -m '(?:^|POSARGS)(?:unit)?POSARGSest'

Obviously, this is undesirable.