it seems apropriate to move the base definition of gui::idi::Descriptor<VIEW>
into view-spec-dsl.hpp and only retain the actual DSL definitions in id-scheme.hpp
The original goal for #1129 (ViewSpecDSL_test) is impossible to accomplish,
at least within our existing test framework. Thus I'll limit myself to coding
a clean-room integration test with purely synthetic DSL definitions and mock widgets
...this was quite an extensive digression, which basically gave us
a solid foundation for topological addressing and pattern matching
within the "interface space"
exploring the idea of a configuration DSL.
As a first step, this could be a simple internal DSL,
implemented as a bunch of static functor objects, which are internally bound
and thus implemented by the ViewLocator within InteractionDirector
