Add thread per provider in ingest
fix(activity): rename notify to read

it will hold status if a given user has read it

SD-684 SD-656
Merge pull request #257 from petrjasek/master

fix(activity): rename notify to read
fix(tasks) - filter items that have tasks associated.
revert reset pass time to live to 24 hours
Merge pull request #258 from amagdas/fix-tasks-take2-of-n

fix(tasks) - filter items that have tasks associated.
Merge remote-tracking branch 'andrew/master'

Conflicts:
	superdesk/io/commands/update_ingest.py
Merge remote-tracking branch 'adrian/revert-ttk'
fix(celery): make it decode objectid/datetime on load