Changes for adding babel, removing global JS

[evanmwillhite]

Add ES6 support (Babel)

Companion PR for Emulsify Gulp's fourkitchens/emulsify-gulp#64

Features:

• Support ES6 syntax
• Uses Babel to compile JS to dist directory using component file path (dist/02-molecules/accordion-item/accordion-item.js
• Uses Sourcemaps for debugging original code in browser
• Removes global.js file and libraries.yml reference (not used often and too easy to misuse)

To test:

• Clone a fresh copy of Emulsify
• composer install
• Change line 6 in package.json to "emulsify-gulp": "fourkitchens/emulsify-gulp#add-babel",
• yarn install
• yarn start
• Verify start command runs without errors
• Verify dist files and sourcemaps are created correctly
• Verify Pattern Lab components with JavaScript work OK

Post-merge

1. In Emulsify Gulp, merge in feat(babel): Add babel to scripts/styleguide-scripts tasks. emulsify-gulp#64 and merge develop into master and deploy master (also in Emulsify Gulp).
2. Edit any instructions for Javascript in Drupal to remove references to global.js

[ModulesUnraveled]

@evanmwillhite I'm getting this error on yarn start

yarn start                                                                           11:39:10
yarn start v0.21.3
$ gulp clean && gulp compile && gulp theme
module.js:472
    throw err;
    ^

Error: Cannot find module 'gulp-uglify'
    at Function.Module._resolveFilename (module.js:470:15)
    at Function.Module._load (module.js:418:25)
    at Module.require (module.js:498:17)
    at require (internal/module.js:20:19)
    at module.exports (/Websites/GitProjects/emulsify-pr-review/node_modules/emulsify-gulp/index.js:16:18)
    at /Websites/GitProjects/emulsify-pr-review/gulpfile.js:16:27
    at Object.<anonymous> (/Websites/GitProjects/emulsify-pr-review/gulpfile.js:18:3)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
error Command failed with exit code 1.

[ModulesUnraveled]

I'm also curious about the repercussions of releasing a new emulsify-gulp. Is that being versioned now? Or will the update break backward compatibility for anyone?

[ModulesUnraveled]

I think I know why I'm getting the uglify error. Seeing if I can fix that now. (TL;DR: Used an existing install, so the yarn.lock was already created)

[ModulesUnraveled]

W00t! Works great!

[ModulesUnraveled]

[ModulesUnraveled]

Ship it!

[infiniteluke]

One test step that was missed here was to ensure the source maps work. Luckily they do!