Change to always show the sensor controls. (#526)

sim/visuals/nodes/ultrasonicView.ts

@@ -1,7 +1,7 @@
-/// <reference path="./moduleView.ts" />
+/// <reference path="./sensorView.ts" />
 
 namespace pxsim.visuals {
-    export class UltrasonicSensorView extends ModuleView implements LayoutElement {
+    export class UltrasonicSensorView extends SensorView implements LayoutElement {
 
         constructor(port: number) {
             super(ULTRASONIC_SVG, "ultrasonic", NodeType.UltrasonicSensor, port);