serious bug in json::delta() fixed

missing content header

json::delta() performance bug fixed

bug fix in pubsub_test and configurable read/write timeout

pubsub.http implements delta updates now

fixed some minor details and compiler errors

let the bayeux parameter max_messages_size_per_client be configurable…

… by the rack interface

serious bug in the bayeux handler fixed

passing true should be considered too; added a test for configurating…

… authorization disabling