Restore wait spinner in tree (missed during Angular transition);
this feedback is important when waiting for the contents of
the Packets node (WTD-644) to load.
Add a utility controller for interacting with
getter-setter style ngModels (similar to ng-model-options
with getterSetter: true, but support for that is not
present in the current version of Angular.) Specifically,
this is used to support the input filter control, which
in turn is used within the autoflow tabular view. WTD-614.
Refactor view switcher to simplify it; treat it
as a representation of a domain object that modifies
an ng-model. This simplifies reuse, e.g. in frames
within a layout. WTD-535.
Use ng-model when communicating state to/from the
tree in browse mode. This will simplify implementation
of the Locator control, which also uses a tree, but
which should not set navigation state. WTD-593.
Add in-line documentation to TreeNodeController, and update
glossary with some clarifying definition.
Additionally, change name from tree-item to tree-node for
consistency.
Part of ongoing transition of commonUI bundles, WTD-574.
