Description

As I was starting on #335, it wasn't clear that I needed to write a manifest file for my test plan, since the docs in USAGE.md don't mention manifests. It would be great to also have a list of what properties are supported / required.

What defines this endeavour to be complete?

• The USAGE.md file is updated to mention that manifests are required and what they are
  • note that changes to the manifest require restarting the daemon
• The required and optional params for a manifest are documented somewhere