Add missing mike42 machine flag to run options

src/main/java/com/loomcom/symon/Main.java

@@ -86,6 +86,9 @@ public class Main {
                     case "beneater":
                         machineClass = BenEaterMachine.class;
                         break;
+                    case "mike42":
+                        machineClass = MichaelBillingtonMachine.class;
+                        break;
                     default:
                         logger.error("Could not start Symon. Unknown machine type {}", machine);
                         return;