+ Implement some stubbed methods in smtk::operation classes
  and test them.
+ Add C++11 callbacks for listening to operator events (all
  of them, not just individual operators like the model-
  operator callbacks did).
+ Add behaviors to the ParaView extensions that do client-
  server communication of selections.
+ Add pqSMTKResourceManager proxy that gets created by
  pqSMTKResourceManagerBehavior upon plugin startup.
  All the selection management stuff in the behavior should
  eventually be moved into the proxy class.
+ Add pqSMTKResource proxy that registers itself with
  the VTK/PV-wrapping of SMTK's resource manager.
+ Fix documentation and add stubs for documenting the
  `smtk/extension` directory.
+ Add Qt extension classes that expose the new
  descriptive phrase classes in `smtk/view`.
+ Use the new qtDescriptivePhraseModel in a panel
  to show resources in ParaView as a behavior.
+ Eliminate client-server duality.
  For now, we work only with PV's built-in server,
  not separate client+server processes.
  This means that there is no need for operator
  forwarding, separate resources on the client and server,
  problems synchronizing the client-only attribute panels
  with models that are modified only on the server, etc.