Add a Dependent to this cell.
The cell's value and most recent change time
Get a List of the Dependents
Get the cell's value
Create a new Cell by applying the function to this cell
Notify dependents of a state change.
If the predicate cell changes, the Dependent will be notified
Remove a Dependent to this cell.
Remove from all dependencies
Get a list of all the cells this Dependency depends on
The Cell notifies the Dependent of the dependency
The Cell notifies the Dependent of the removed dependency
(Since version 2.5) please used the correctly spelled unregisterFromAllDependencies