[inspector] Fix router push state
[inspector] Add Data pane functionality
Cleanup view and model serializing

+ start using inspectValue instead of serializeObject for inspecting a
value (duh)
+ start using serializeObject for serializing an object
+ make regionInspector an agent instance method (helps when we're
consistent)
+ add serialized content to data row and info
+ normalize a lot of content now that we're using serializeObject
everywhere
[inspector] Extract SidebarPane behavior
memoize / clean up inspect