Pass tox posargs to pylint

[scop]

Description:

Being able to pass arguments to pylint is useful, for example --jobs=N, -f parseable etc.

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

[scop]

I also experimented with setting the number of jobs to various values locally and in Travis.

In Travis, it seems setting it to anything but 1 just slows things down.

Locally for me (dual core hyperthreading laptop --> 4 cpus) good values include 2 or 3 jobs. 4 (i.e. the same as 0) makes the system too unresponsive for other work, if not run with nice, and with nice, gives pretty much same results as 3 without it, with similar effect on responsiveness.

So, worth considering in addition to this change would be to add jobs=0 or jobs=2 to pylintrc, and forcing Travis to serial linting with -- --jobs=1: 0 would bring largish speedups at cost of making system unresponsive, 2 would be a rather conservative default that would give ~2x speedup on most systems, while possibly hurting lower powered ones to some extent. In any case, the default can be overridden using --jobs=N on the command line. Thoughts, should something like this be additionally done? Personally somewhat torn over this, perhaps somewhat leaning towards not trying anything past this commit but leaving it to local invocations, e.g. nice tox -e pylint -- --jobs=0.

[andrey-git]

Thanks!
Lets merge this as-is meanwhile.