Drives can now deliver activity events.

Activity/Source.hpp

@@ -0,0 +1,24 @@
+//
+//  ActivitySource.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/05/2018.
+//  Copyright © 2018 Thomas Harte. All rights reserved.
+//
+
+#ifndef ActivitySource_h
+#define ActivitySource_h
+
+#include "Observer.hpp"
+
+namespace Activity {
+
+class Source {
+	public:
+		virtual void set_activity_observer(Observer *observer) = 0;
+};
+
+}
+
+
+#endif /* ActivitySource_h */