[wsia][wsrp-interfaces] Object model

To jumpstart this discussion, here's a pretty basic object model I sketched
out.  Let's comment to both lists.  I'm attaching a jpg version, as well as
the original Visio document if you'd like to annotate away...

I'm basically starting from the 0.21 spec, culling the interface and
parameter sections as they now stand to work up a model.

Alan