Created a delegate in ShellModel to propagate data changes to the ViewModel
When in design mode, show new competition only.
Added placeholder for ClubsView user control.
Added placeholder for WeaponsView user control.
Added placeholder for StationsView user control.
Added placeholder for ShootersView user control.
Added placeholder for GeneralView user control.
Added placeholder for ManageResultsView user control.
Added placeholder for ResultsView user control.