Add feature to automatically update document title on idle and timeout.

[moribvndvs]

It would be useful for this module to provide a way of automatically updating the document title when the user becomes idle or is timed out, and restore the original title when the user is active again.

Additional goals:

1. Touchless/minimal configuration: just monitor the appropriate ng-idle events and go.
2. Allow dynamic update of messages used in the title at runtime.