Expanding message registration exception message as it is a little misleading

The exception message states that the messages must implement, IMessage, IEvent or ICommand however this may not have been the cause of the exception. If the user has configured NSB such that the message types have never been registered (e.g. NSB has not scanned the required assembly) then they will also get this error message even though their messages implement the correct interfaces.
Closws Housekeeping #65
Added LookupId prop, fixes #1640
Reference to System.Management.Automation in NServiceBus.PowerShell is now set to be not version-specific, fixes #1647
Removing unnecessary files from nservicebus.tools package
Fixed bug in T4Scaffolding init.ps1, see https://mvcscaffolding.codeplex.com/workitem/60

Included T4Scaffolding as part of our hosts packages with patched version.
bump Janitor to fix dispose order

fixes #1390
remove T4 from nuget dependencies
add failing test for message mapping order
moved callback invocation into behavior
dont commit vshost crap

bad @andreasohlund
try tagging on release branch
fix nuget version
remove impersonation

fixes  #1642
mark ICircuitBreaker as obsolete

fixes #1663
obsolete IMessageMapper

fixes #1624
make StaticMessageRouterTests explicit
Ensuring ThroughtputLimiter Stop/Start methods can't be called concurrently.
Resetting numberOfMessagesProcessed back to 0 at Start, fixes #1660

Avoiding a possible deadlock between the Stop and MessageProcessed methods.
Obsolete all Bus.CreateInstance

fixes #1607