link-store: ensure latest-first ordering of state
link-store: ensure latest-first ordering of state

We may %hear or %read content that was posted some time ago, so we need
to make sure we add it at the appropriate position (wrt timestamp)
rather than just sticking it at the head of the list.

jfranklin9000/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,jfranklin9000/urbit,jfranklin9000/urbit,jfranklin9000/urbit,urbit/urbit,jfranklin9000/urbit,jfranklin9000/urbit,urbit/urbit,ngzax/urbit,jfranklin9000/urbit