Java example code for Getting Started

* WiP on Java version of new Hello World

Done:
- implementation for first 3 sections
- tests for first 2 sections

To do:
- formatting
- tests for section 3
- section 4 and 5
- hooking the fragments into the docs themselves

* Finish tutorial_03 conversion

* Converted tutorial 04

* Convert step 5 scala->java

* Reformat Java code (thx IntelliJ IDEA)

* Format using 2 spaces

Really it'd be neat to have something like scalariform for the Java code, too

* Make fields 'private final'

* Make message classes 'public static final'

* Use primitive long/double where possible

* sender() -> getSender()

* Static import of org.junit.Assert....

* Final actor fields

* println() the instruction to hit ENTER to quit

* Use jdocs package for quickstart, too

* Use helper methods for message handling

* Compare doubles specifying a delta

* Keep tutorial steps independent

akka-docs-new/src/test/java/jdocs/tutorial_5/IotMain.java

@@ -0,0 +1,29 @@
+/**
+ * Copyright (C) 2009-2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+package jdocs.tutorial_5;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+
+import java.io.IOException;
+
+public class IotMain {
+
+  public static void main(String[] args) throws IOException {
+    ActorSystem system = ActorSystem.create("iot-system");
+
+    try {
+      // Create top level supervisor
+      ActorRef supervisor = system.actorOf(DeviceManager.props(), "iot-supervisor");
+
+      supervisor.tell(new DeviceManager.RequestTrackDevice("mygroup", "device1"), ActorRef.noSender());
+
+      System.out.println("Press ENTER to exit the system");
+      System.in.read();
+    } finally {
+      system.terminate();
+    }
+  }
+
+}