Options for @ViewScoped to specify where associated state is saved

The current implementation of @ViewScoped in JSF 2.2 is tied to the session scope, which is a server side storage.

I'd like to propose to have several options for @ViewScoped to specify where the state associated with it is saved.

The options can be as follows:

* Follow the state saving setting applicable for that view (_this is approximately the JSF 2.1 and earlier behavior_)
* Always session (_this is the JSF 2.2 behavior_)
* Always client (_new option_)

Start by reading the current @ViewScoped implementation and the JSF state-saving behavior referenced in the issue. Determine how the existing session-backed behavior relates to view state saving, then define and implement the requested choices: follow the view setting, always session, or always client.

Written by the indexing model from the issue text.