A user can edit and save changes to an interactive.

This will allow changes to interactives that have *not* been imported into the CouchDB.
Added some model/unit tests
Allow the interactive updates to show up in about pane.

The updates made when updating an interactive with the interactive editor
were not showing up in the about pane or the page's title/subtitle.
Allow the interactive changes made before saving to show up in the about pane.