First new SphereStudio plugin, Sound Test

Inspired by the "Sound Test" feature in old Kirby games! This way you don't have to open a new tab for music and interrupt the script/other document you happen to be working on.  The plugin is still rough around the edges and needs a LOT of polishing, but it's functional and appears to be bug-free.

Update: So what started as a single-commit pull request has apparently ballooned to 7 commits - can you tell I'm a perfectionist? ;-)