Finally cracked ObservableAsPropertyHelper..

Remove dependency on MessageBus for Scores and NewMatch VM. Rather
observe for changes to NewMatchVM as it is a child VM for MatchScores
Fixed broken tests after refactoring NewMatchControl ViewModel
Create Action Commands for Game actions
Refactor GameAction class to be a VM.

Add ReactiveCommand to IGameActionViewModel to enable direct binding the
ItemsControl item
Match Score - Able to add point for a game
Match Score - Adding points for both players
Staged..Scoring Engine