Ergonomics / Polish / Initial Experience "Punch List"

[wycats]

• Can't use async function out of the box due missing regeneratorRuntime (Can't use async / await out of the box #55)
• Sourcemaps seem broken (Sourcemaps seem to have issues #56)
• Integration with npm packages should be documented and/or improved (Document (and improve) using npm packages #57)
• Guides need a quick (optional) introduction to TypeScript and pointers to other resources. (Context around TypeScript glimmer-website#65)
• Guides need to document args vs. attrs (and more generally, templates!) (Template Guide glimmer-website#66)
• Nested components are broken (Nested components don't appear to work as documented #84)

This issue is not intended to supersede #54, which is largely focused on technical and internal issues.

[locks]

Added #84.

[locks]

Moved to https://github.com/glimmerjs/glimmer-application/projects/1.