Cleanup stale/non-portable files

[mariusstrom]

Removed MacOS .DS_Store files from repo and added to .gitignore to prevent reintroduction

[spuder]

Thanks for fixing this. I was going to open the same PR.

Ideally users should have a global gitignore to ignore .DS_Store files. But in the absence of a proper global config, adding .DS_Store to the repo .gitignore is the next best option.

echo .DS_Store >> ~/.gitignore_global
git config --global core.excludesfile ~/.gitignore_global