CORS Configuration

Thanks to @ru3fu5z for implementing CORS-Configuration!

Thanks to @andrehoffmann30 for the JS-Bugfix!

What's Changed

• FEATURE add CORS whitelist by @ru3fu5z in #52
• BUGFIX: adjust conditions to prevent double insert of script by @andrehoffmann30 in #53

Full Changelog: 5.0.5...5.2.0