website: Add a Google+ presence

Since we use Google+ to share our news, this add a logo on the menu bar,
which links to the Buildroot profile.

[Peter: change link to Buildroot account]
Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/header.html

@@ -16,6 +16,10 @@
       .button_column{
         width: 430px;
       }
+      .gplus {
+        float:right;
+        margin: 10px 0 0;
+      }
     </style>
 
     <!-- Le HTML5 shim, for IE6-8 support of HTML5 elements -->
@@ -43,6 +47,7 @@
               <li><a href="/contribute.html">Contribute</a></li>
               <li><a href="/sponsors.html">Sponsors</a></li>
             </ul>
+            <a class="gplus" href="https://plus.google.com/100084591154899263420/posts"><img src="images/gplus.png" height="28" width="28"></a>
           </div><!--/.nav-collapse -->
         </div>
       </div>