Description of Pull Request:

Use the Babel standalone compiler to compile v-play examples and playground user supplied code, to allow ES6 support on older browsers (mainly IE)

Many of the documentation live examples do not work in IE 11, nor does ES6-ish code in the Playground.

Example (which should show the alert live example above the example code):

As a bonus of using babel, JavaScript compile errors provide better debugging (i.e line numbers, etc) in the Playground log:

Also adds overflow-x: auto to all live rendered examples. Fixes #1816

Todo:

• playground page (play.vue)
• v-play directive
• make async/lazy load of babel-standalone
• Figure out why polyfills (babel-polyfill / core-js) is not working in IE 11 (specifically the WeakSet polyfill)
• Minor style adjustments

PR checklist:

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Enhancement to an existing feature
• ARIA accessibility
• Documentation update
• Other, please describe: Docs site

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact:

The PR fulfills these requirements:

• It's submitted to the dev branch, not the master branch
• When resolving a specific issue, it's referenced in the PR's title (i.e. fixes #xxxx[,#xxxx], where "xxxx" is the issue number)
• The PR should address only one issue or feature. If adding multiple features or fixing a bug and adding a new feature, break them into separate PRs if at all possible.
• PR titles should following the Conventional Commits naming convention (i.e. "fix(alert): not alerting during SSR render", "docs(badge): Updated pill examples, fix typos", "chore: fix typo in docs", etc). This is very important, as the CHANGELOG is generated from these messages.

If new features/enhancement/fixes are added or changed:

• Includes documentation updates (including updating the component's package.json for slot and event changes)
• New/updated tests are included and passing (if required)
• Existing test suites are passing
• The changes have not impacted the functionality of other components or directives
• ARIA Accessibility has been taken into consideration (does it affect screen reader users or keyboard only users? clickable items should be in the tab index, etc)

If adding a new feature, or changing the functionality of an existing feature, the PR's description above includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)