FCPInterface: Remove sendAllScoreValues(), not used anymore

- Was being used in
SubscriptionManager.Subscription.synchronizeSubscriberByFCP(), which
has been replaced by the recent commits which send synchronizations as
regular ObjectChangedNotifications
- Also, remove support for calling handleGetScores() with
request=null since sendAllScoreValues() was the only user of that
feature.
SubscriptionManager: Add code quality TODO

Its about the code duplication introduced by the previous commits.
SubscriptionManager: Organize imports.