Prevent a double-initialisation crash.

Changelog

• If you already have the extension in the browser, it's bypasses will be used.
• If you don't, then the game's Rouselle Stage 2 will be used.
• Added newgrounds CDN link into allowed sites.

Known Issues

• If your extension is older than the game's Stage 2 it will break (not vice versa), please update the extension.
• Opera still did not make the WASM export a public thing. Yes. This is indeed a known issue.
• Chrome on Windows is still being a bitch and doesn't let me make .crx files, blame Chrome. Which is why no crx/xpi this time too. Install from folder.