3262 with Marked for Later losing current indicator due to pagination

http://code.google.com/p/otwarchive/issues/detail?id=3262

If your to-read list was paginated, the Marked for Later button at the top stopped looking like it was pressed down when you navigated to the second (or third or...) page.

Alternative solution: using params.merge, which is what we do in other places like bookmarks/recs.