Add method to clear sim targets (#733)

Closes #731

photon-lib/src/main/java/org/photonvision/SimVisionSystem.java

@@ -119,7 +119,6 @@ public class SimVisionSystem {
         dbgField
                 .getObject("Target " + Integer.toString(target.targetID))
                 .setPose(target.targetPose.toPose2d());
-        ;
     }
 
     /**
@@ -139,6 +138,15 @@ public class SimVisionSystem {
         }
     }
 
+    /**
+     * Clears all sim vision targets. This is useful for switching alliances and needing to repopulate
+     * the sim targets. NOTE: Old targets will still show on the Field2d unless overwritten by new
+     * targets with the same ID
+     */
+    public void clearVisionTargets() {
+        tgtList.clear();
+    }
+
     /**
      * Adjust the camera position relative to the robot. Use this if your camera is on a gimbal or
      * turret or some other mobile platform.