fix project digests when args are encoded in JSON
fix project digests when args are encoded in JSON

When an emailer is enqueued in Resque its arguments are encoded in JSON
and then decoded, thus hashes must be converted to
HashWithIndifferentAccess.

irfanah/teambox,vveliev/teambox,vveliev/teambox,irfanah/teambox,nfredrik/teambox,rahouldatta/teambox,irfanah/teambox,teambox/teambox,nfredrik/teambox,vveliev/teambox,rahouldatta/teambox,nfredrik/teambox,vveliev/teambox,irfanah/teambox,rahouldatta/teambox,teambox/teambox,teambox/teambox,nfredrik/teambox