- hub now defers subscription state updates until after verification, per spec
- hub now supports synchronous verification when requested (if async is not requested after)
- client now requests synchronous verification (it's a bit safer)
- cleanup on subscription logging/error responses
- actually udpate feedsub.last_update when we get a new PuSH update in
- move incoming PuSH processing to a queue handler to minimize time spent before POST return, as recommended by PuSH spec. When queues are disabled this'll still be handled immediately.
