Add a description to the extension

Author: plaa

src/net/sf/openrocket/example/ThrustScaler.java

@@ -22,6 +22,12 @@ public String getName() {
 		return "Thrust scaling \u00D7" + getMultiplier();
 	}
 
+	@Override
+	public String getDescription() {
+		// This description is shown when the user clicks the info-button on the extension
+		return "This extension multiplies the thrust of motors by a user-defined multiplier.";
+	}
+	
 	@Override
 	public void initialize(SimulationConditions conditions) throws SimulationException {
 		conditions.getSimulationListenerList().add(new ThrustScalerSimulationListener(getMultiplier()));