Update npm-ignore rules for all npm published packages

[usergenic]

• Normalized all the .npmignore files to standard form with leading / and removed unnecessary automatic exclusions like node_modules and missing files like .clang-format.
• Updated CHANGELOGs for packages which had .npmignore changes so the next release picks them up.
• Opportunistic clean-up here in that I also removed unused per-package-top-level files like .github and appveyor.yml.
• One or two .js files may have had formatting slightly updated because clang-format.

Here's a gist of the results of the new ignores: https://gist.github.com/usergenic/04c04c01623c0c8342bdbfb336cfdf63

[rictic]

This seems reasonable, but it's tricky to be certain that it's correct or to test that it's correct, and it can break a release if it's wrong.

[usergenic]

@rictic you make a good point. Probably best way to visualize the effects of changes and mitigate risk is to do packages as separate PRs including a diff of npm packaged files in the descriptions.

[rictic]

Yeah, that'd be way easier to review! Sorry for the added friction!