Update instructions to get the API key for the G+ sample. (#419)

The instructions to obtain the API key are outdated and require some googling to obtain the concrete steps. Pointing to accurate and detailed instructions from the G+ documentation (which should be kept up to date in the face of changes).

Author: omar-estrada

samples/googleplus-simple-cmdline-sample/instructions.html

@@ -19,10 +19,13 @@ <h3>Register Your Application</h3>
     <li>Visit the <a href="https://code.google.com/apis/console/?api=plus">Google
         apis console</a>
     </li>
-    <li>If this is your first time, click "Create project..."</li>
-    <li>Activate the Google+ API and agree to the terms of service</li>
-    <li>Click on "API Access"</li>
-    <li>Enter the "API Key" shown under "Simple API Access" into the API_KEY constant.</li>
+    <li>If this is the first you run the sample...</li>
+    <ul>
+      <li>Click "Create project..."</li>
+      <li>Fill out the project info. You can give the project any name (e.g., "Plus Command Line Sample"). Click "Create".</li>
+    </ul>
+    <li>Follow <a href="https://developers.google.com/+/web/api/rest/oauth#acquiring-and-using-an-api-key">these intructions</a> to obtain the API key.</li>
+    <li>Set the API_KEY constant in GooglePlusSample.java to the key gotten in the previous step.</li>
   </ul>
 
   <h3>Checkout Instructions</h3>