Improve invalidation blocking
* src/mail.cpp (do_parsing): Don't use invalidation_lock. We now have block invalidation. * src/mailitem-events.cpp (Read): Delay invalidate. * src/windowmessages.cpp (delayed_invalidate_ui): Take sleep param. (INVALIDATE_UI): Respect invalidation blocked. * src/windowmessages.h: Update accordingly.
This works much better then the try to archive minimizing
invalidations by using a lock.