GUI -- Created NavService and implemented simple navigation (click on the bird!)

Change-Id: I2bda5a3a1b279167194a84564408760eebcb59fd
diff --git a/web/gui/src/main/webapp/app/fw/nav/nav.js b/web/gui/src/main/webapp/app/fw/nav/nav.js
new file mode 100644
index 0000000..7ab6981
--- /dev/null
+++ b/web/gui/src/main/webapp/app/fw/nav/nav.js
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2014,2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ ONOS GUI -- Navigation Module
+
+ @author Simon Hunt
+ @author Bri Prebilic Cole
+ */
+(function () {
+    'use strict';
+
+    // injected dependencies
+    var $log;
+
+    // internal state
+    var navShown = false;
+
+    function updatePane() {
+        var vis = navShown ? 'visible' : 'hidden';
+        d3.select('#nav').style('visibility', vis);
+    }
+
+
+    function showNav() {
+        navShown = true;
+        updatePane();
+    }
+    function hideNav() {
+        navShown = false;
+        updatePane();
+    }
+    function toggleNav() {
+        navShown = !navShown;
+        updatePane();
+    }
+
+    angular.module('onosNav', [])
+        .controller('NavCtrl', [
+            '$log', function (_$log_) {
+                var self = this;
+                $log = _$log_;
+
+                self.hideNav = hideNav;
+                $log.log('NavCtrl has been created');
+            }
+        ])
+        .factory('NavService', ['$log', function (_$log_) {
+            $log = _$log_;
+
+            return {
+                showNav: showNav,
+                hideNav: hideNav,
+                toggleNav: toggleNav
+            };
+        }]);
+
+}());