Added a simple 'HelloWorld' java example. This can be quickly used to…

… demonstrate different issues in pants without the complexities of the `examples/src/java/com/pants/examples/hello/main` target that is used to demonstrate more features of pants, like bundling, resources, etc.

Testing Done:
./pants run examples/src/java/com/pants/examples/hello/simple

Ran ./build-support/bin/publish_docs.sh  and looked at the first_tutorial page.

Bugs closed: 1180, 1365

Reviewed at https://rbcommons.com/s/twitter/r/2028/

examples/src/java/com/pants/examples/hello/simple/BUILD

@@ -0,0 +1,8 @@
+# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+jvm_binary(name = 'simple',
+  source = 'HelloWorld.java',
+  main = 'com.pants.examples.hello.simple.HelloWorld',
+)
+

examples/src/java/com/pants/examples/hello/simple/HelloWorld.java

@@ -0,0 +1,17 @@
+// Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+package com.pants.examples.hello.simple;
+
+/**
+ * A simple example that is runnable from within pants:
+ *
+ * ./pants run examples/src/java/com/pants/examples/hello/simple
+ *
+ */
+public class HelloWorld {
+
+  public static void main(String[] args) {
+    System.out.println("Hello World!");
+  }
+}

src/docs/first_tutorial.md

@@ -279,7 +279,13 @@ will still compile them since it knows it must compile before it can
 test.
 
     :::bash
-    $ pants goal test src/java/com/myorg/myproject tests/java/com/myorg/myproject
+    $ pants test src/java/com/myorg/myproject tests/java/com/myorg/myproject
+
+**Run a binary**<br>
+Use pants to execute a binary target.  Compiles the code first if it is not up to date.
+
+    :::bash
+    $ ./pants run examples/src/java/com/pants/examples/hello/simple
 
 **Get Help**<br>
 Get the list of goals: