merging #2077
Merge remote-tracking branch 'origin/hashtalk' into notifications-refactor
removed total count
closes #2074

when new notifications are pushed to uids clear their old notifications.
markAsRead improvement

takes in an array of tids instead of marking topics read 1 by 1
same for the category.markAsRead function
Merge remote-tracking branch 'origin/hashtalk' into notifications-refactor