Implement initial save button, add protection against calling next/done multiple times in a plugin.
Track unsaved changes state.
Make all cells editable by default, clean up the event proxying functions.
Remove user owner styles.
Block window unloads when the notebook has not been saved.
Remove the authentication banner.
Remove read only title blocker.
Implement initial modal popup steps.
Autosave to Github if we are the current owner and authenticated.
Fix failing test cases.
First pass at implementing an OAuth modal before the popup.