Apply Modern Standards

[marlowpayne]

Reviewers: @jansepar @fractaltheory @mikenikles @MikeKlemarewski

Changes

Update Bellows to some modern best-practices

• Prep for publishing to NPM
• Remove Zepto support in favor of jQuery
• Migrate all dependencies to NPM, remove Bower
• Migrate JS linting to eslint
• Migrate SCSS compilation to libsass
• Lint SCSS with sass-lint
• Update circleCI config with modern testing steps
• Add some GitHub templates for contributing, issues, and PRs

Todos:

• Add a PR template
• +1
• +1 (Major version bump)
• Update package.json and Readme with a non-conflicting NPM package name

How to Test

• Checkout code
• Refresh node modules with rm -rf node_modules && npm install
• Test with grunt test or grunt test:browser
• Check that the examples still work with grunt examples
• Check out this branch of Extra Stores that uses this new code for its Bellows

[jansepar]

💥

[aerykk]

💥 Tests pass. LGTM 👍

[henryh15]

👍 LGTM! All tests pass.