thread stream no longer depends on anything

* does not depend on parent board

* does not use first message
post stream no longer depends on threads
update stat logger to use new labeler methods
use a single statlogger instance
use statlogger end method in index
use a single instance of logfile
board import no longer uses a handler

* handles its own error logging

* handles its own stat logging

* does not need to spawn thread imports
user import no longer uses a handler

* handles its own error logging

* handles its own stat logging
thread import no longer uses a handler

* does not need to handle parent board

* handles its own error logging

* handles its own stat logging

* does not need to spawn post imports
post import no longer uses a handler

* does not need to handle parent thread

* handles its own error logging

* handles its own stat logging
category import no longer uses a handler

* handles its own error logging

* handles its own stat logging
stats now includes category
importer index keeps an array of all imports
use async to iterate through imports
index callback called by async