renamed and transformed IOutgoingMessages to IInvocationContext
bit of an adjustment to the Runtime namespace
lot of spiking for the new invocation model
moved the Callback as a property on Envelope
Envelope's message property is a lazy behind the scenes now in preparation for more work
IEnvelopeSerializer.Deserialize returns the deserialized message, precursor to more changes
made Envelope take care of message deserialization itself as a lazy usage of the IEnvelopeSerializer
CHECKPOINT:  Compiling after all the big changes for Envelope to EnvelopeToken
checkpoint:  fixed the in-memory tests
checkpoint:  fixed the easy UT failures
checkpoint:  fixed the delayed processing UT failures
checkpoint:  introduced HandlerPipeline
added DelayedMessageHandler
added the delayed and response envelope handlers
checkpoint: feeling like the handler pipeline is wrapped up
checkpoint:  message invoker UT's are fixed and the obsolete ones are eliminated
checkpoint: registering the IEnvelopeHandler's
completely switched over to the new IHandlerPipeline internals
finished rebasing the HandlerPipeline restructuring on top of the LightningQueues changes