/api/live/create: Include new thread ID in JSON response.
Move websocket URL to /live/{event}/about.json.

This allows API clients to get the URL and use it.
Document the API.
OAuth: Add scopes to some endpoints

Adds "read" scope to GET_listing
Adds "submit" scope to POST_update
Adds "edit" scope to striking/deleting updates
OAuth: Add scopes to the rest of the API endpoints.