Log a warning when /admin/alive returns an error
Added a get_live_sql function

Returns the sql that get_live_articles_from would use to search. Can
be used to avoid search expressions becoming too complex, speeding up queries.
Simplified article queries
Generate a simpler query
Don't prefetch folders

Prefetching is VERY slow, and ends up slowing down the entire request
rather than speeding it up.
Added several indexes