We're now starting to resolve headers from the pipeline as we're moving
towards a more clean way of managing headers
Cleaning up the static outgoing headers
Getting rid of the _currentMessageBeingHandled static
Making sure that headers are applied to outgoing messages and that headers
on the physical message is transfered to the incoming logical messages
Fixing the failing DataBus tests and moving the databus over to behaviors
Switching back to using the InMemory saga storage by default until we
figure out why the tests are unstable when using Raven
Changed to outgoing headers to be stored in the pipeline context
Fixing a tripple lookup in the databus
Making the supressed scopes more narrow in the databus
Fixing a few lookups
Merge pull request #1792 from Particular/header-cleanup

Header cleanup
move Impersonate switch into ImpersonateSenderBehavior
Need to distinguish between different versions of Distributor
Merge branch 'develop' into Issue_1732