Added [WIP] tag in an attempt to get the flake8 --diff checks going, not sure . that's going to be feasible though, will likely have to remove altogether.

Started working on this on another branch, the flake8 -diff checks are still tough to integrate at the commit time. I am not a fan of having this check strictly in the CI (this takes too long to hear back that you have an extra space, or your line is too long).

I've created https://github.com/pyqtgraph/pre-commit-hooks and have been trying too make a hook to run the flake8 diff, but so far I haven't been able to get it working as I intended.

If anyone has any suggestions on how to integrate that check at commit time, let me know.

ugh....what on earth is happening w/ creating conda environments in the CI process?

something has changed on azure pipelines with respect to how macOS and conda task work; this will take be a little while to debug.

Gave up on trying to get linting checks to happen at the pre-commit time (doing a flake8 check on a file basis is fine, but doing it on the --diff I'm not sure can be done).

I had to modify the CI script substantially for a few reasons

• conda 4.7.X has problems with python2 environments
  • fixed by manually downloading miniconda2 4.6.14 and installing it over the existing miniconda setup
• -c conda-forge pyside on linux has some missing symbol issue that's an indication of a build related problem, but given its age, it won't be fixed (luckily -c defaults pyside` doesn't have this issue

Throwing WIP label as i realized i never actually tested the 100kb size limit on the size check...will want to do that before this is merged, I'll test on another branch

Cleaned up the PR, I think this is ready for review; only thing I couldn't do is get the flake8 --diff check to work at pre-commit time; oh well.

Thanks @campagnola I'll go ahead and merge as you gave approval

Thanks for everyone's patience with me on this,...this took me way too long to sort out, and there will likely be changes coming in the future with pytest-nunit, updates to pyqtgraph-core and doc builds.