🚑 resolves #717 do not use an advanced compilation level (#719)
🚑 resolves #717 do not use an advanced compilation level (#719)

Code produced with advanced level is invalid because Opal is using Object.defineProperty.
Mogztter/asciidoctor.js,asciidoctor/asciidoctor.js,asciidoctor/asciidoctor.js,Mogztter/asciidoctor.js,Mogztter/asciidoctor.js,asciidoctor/asciidoctor.js,asciidoctor/asciidoctor.js,asciidoctor/asciidoctor.js,asciidoctor/asciidoctor.js,Mogztter/asciidoctor.js,Mogztter/asciidoctor.js,Mogztter/asciidoctor.js