Testing defer message invocations

added expectations for Bus.Defer + unit tests
Testing defer saga invocations

added invocations for expecting no timeouts
Merge pull request #1848 from chrisbednarski/TestingDefer

Testing of Bus.Defer
Only one worker should subscribe to the event from the distributor. Fixes #1925

relates to #1925.

Reverted changes to ReturnAddressRewriter. Injecting the distributor data address directly to the MessageDrivenSubscriptionManager.
Added HostDisplayName header
Merge pull request #1927 from Particular/fix-1925

Relates to #1925
Added DisplayInstanceIdentifier to HostInformation and we are now initialising by default DisplayName to be the MachineName
Renamed the new headers to our new convention. Also marked the host info
as a unsuported api
Making it work even thought it doesn't make sense
Removed cmd line args as it could contain sensitive information
Merge pull request #1932 from Particular/HostInfoChanges

Added DisplayInstanceIdentifier to HostInformation
Header should be a diagnostics one.