Now supports both callbacks and pubsub seamlessly

This is done by using a separate queue for replies to make sure they are
processed by the scaled out instance the sent the request

Closes #35

Added test to cover callbacks when scaled out

Stopped using ScaleOut.X setting

Refactored the dequer to allow better control over the queue receiving
from

Test and naive impl up callback queue receive

Cleaned up the secondary receives

Reading from settings

Make sure callback queue gets created

Allow target queue on replies to be overriden

Make sure to set and promote the header

Tests are now green localy

Added settings for the callback receiver

Temp fix for invalid acceptance test
Updated to stable v5 core
Renamed the callback header behavior
Better string format
No need for a list of secondary receivers
Removing invalid stack trace asserts

See - https://github.com/Particular/NServiceBus/issues/2399
Merge pull request #42 from Particular/seamless-scaleout

Seamless scaleout for both callbacks and pubsub