Add loaded item to the exposed API.

Also some groundwork for the position/cue/intro items.
Play him off, rubocop.
Another load of unsorted changes, sorry
Clean up main invocation.

Also move the queue initialisation, so it can be attached to the
web app for sending requests.
Add first PUT method and support therefor.

This includes renaming the BapsCodes so they make sense from both a
request and response point of view.

Some new logic has been added for parsing and flagging errors on
the PUT method, but things are still pretty flimsy.