* Each model.User now has a current storage bytes and a rate plan.
* model.User.to_dict() updated accordingly.
* Minor Scheduler.add() change to bail of the given thread is None.
* controller.Users.current() returns current user's rate plan details.
* controller.Users.update_storage() now takes an optional callback.
* Various methods in controller.Notebooks responsible for calling controller.Users.update_storage().
* Added rate plan details to config/Common.py.
* Added quota utilization colors to style.css.
* Implemented quota utilization calculation and display in Wiki.js.
Still to-do: Return updated storage bytes where appropriate in controller.Notebook and update the
client accordingly.
* Made sure the trash is not exposed by the read-only notebook view.
* Modified model.User.check_access() to consider read-write access to a
notebook to be sufficient for access to that notebook's trash.
* Modified controller.Users so new users are created with a notebook that
has a trash.
* Changed controller.Notebooks so deleted notes go to the trash (if any).
Dan Helfman