Migrate from ScriptProcessorNode to AudioWorklet

[BillyWM]

After many years of ScriptProcessorNode being officially deprecated without any actual replacement, AudioWorklet is finally live in Chrome 66 and Opera.

This should help with playback problems

https://developers.google.com/web/updates/2017/12/audio-worklet

Still an open Bugzilla ticket for Firefox support. Will want to feature-detect and allow falling back to the old system. Progress on other browser support unknown (At a glance, it doesn't seem to be coming to Edge soon).

Also need to revisit if these primitives are being used correctly for JSModPlayer. Good discussion about the difficulties of dynamic audio here: https://github.com/WebAudio/web-audio-api/issues/1322