warning mentions preview into area where actual content would be

Also, since the root component connects to the stream that updates home/notification columns,
there is pretty much no case for refreshing those columns beyond initial load. So, move the
loading of those columns into the root component, to prevent unneccessary reloads when switching tabs
on mobile or resizing desktop window between mobile/desktop layouts

entire timelines (only fetch since last known ID). Side effect: account
timelines no longer update in real-time