Deep checking of @ComputedProperties is now default if one depends on another model class

Moving the ability to control whether the value change is transitive or not out from the public API. Will make it default.

Documenting newly added Proto object mehtods

Only access the observer field under the GLOBAL lock

Don't initialize observers when the watched property is not known

Encapsulating all logic into Observers top level class

Using classical java.util classes minimizes the chance I will do mistake when coding linked list myself

Adding the original test that motivated these changes. The Angular's ToDo sample.

Additional tests

Don't duplicate head of the linked list