Modified RaceClock to support arbitrary start times

- Amended RaceDataSource interface to require time instead of mark for calculating time.
#story[758]

visualiser/src/main/java/seng302/Controllers/RaceController.java

@@ -133,7 +133,7 @@ public class RaceController extends Controller {
 
         //Initialize save annotation array, fps listener, and annotation listeners
         //timezone
-        RaceClock raceClock = new RaceClock(raceData.getMark());
+        RaceClock raceClock = new RaceClock(raceData.getZonedDateTime());
         timeZone.setText(raceClock.getTimeZone());
         initializeFPS();
         initializeAnnotations();