Made collapse turn off editing

This PR:

- Makes `gi-collapsed` a single class on the `.gi-user-list` element, rather than a class applied to three separate elements
- Makes `gi-editing` applied to the `.gi-user-list` element rather than the options element alone
- Removes `gi-ediiting` (editing mode) from the element when the user-list is toggled
- Adds a substantial amount of tests