handle time.com, and scrolling article page

final version
So time.com also displays some ad content and "In this issue" pages in the scroll list that Zotero cannot import. (1) we need to redo detection as the user scrolls and (2) we need to not display a URL bar icon when this is the case.

We can do (1) via `Zotero.monitorDOMChanges`, but (2) is currently not going to work, because the page will still be detected by Embedded Metadata. So for now I'll just leave this here as a note.