Redesign the WorkflowController to be servlet API neutral

Right now, the WorkflowController can only function within a servlet container. It is reliant on the RequestDispatcher of the container. It's method signatures do not reflect this reliance, and the internal structure can be altered to be made more robust if and when it becomes necessary.

In order to do this, a lot of the logic of the WorkflowController class needs to be abstracted into business rules. A protocol evaluator will need to be written that can decide how to respond to incoming requests from different protocols. SMTP in might trigger SOAP-RPC out, for example.

Error handling, L10n and other common factors will also need to be taken into account.