fix(app): ensure headings are visible when navigating to in-page anchors

Closes #477

public/_includes/_main-nav.jade

@@ -1,4 +1,4 @@
-md-toolbar(class="main-nav background-regal l-pinned-top l-layer-5")
+md-toolbar(class="main-nav background-regal l-pinned-top l-layer-5",scroll-y-offset-element)
   nav
     h1 <a href="/" md-button>Angular <sup>by Google</sup></a>
 

public/_includes/_scripts-include.jade

@@ -6,7 +6,7 @@ script(src="/resources/js/vendor/lodash.js")
 
 
 <!-- Angular Material Dependencies -->
-script(src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js")
+script(src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.js")
 script(src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular-animate.min.js")
 script(src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular-aria.min.js")
 script(src="https://ajax.googleapis.com/ajax/libs/angular_material/0.8.3/angular-material.min.js")
@@ -24,6 +24,7 @@ script(src="/resources/js/directives/code.js")
 script(src="/resources/js/directives/code-tabs.js")
 script(src="/resources/js/directives/code-pane.js")
 script(src="/resources/js/directives/code-example.js")
+script(src="/resources/js/directives/scroll-y-offset-element.js")
 
 
 <!-- GA -->

public/resources/js/directives/scroll-y-offset-element.js

@@ -0,0 +1,5 @@
+angularIO.directive('scrollYOffsetElement', ['$anchorScroll', function($anchorScroll) {
+  return function(scope, element) {
+    $anchorScroll.yOffset = element;
+  };
+}]);

public/resources/js/site.js

@@ -19,4 +19,8 @@ var angularIO = angular.module('angularIOApp', ['ngMaterial'])
     .accentPalette('purple', {
       'default': '200' // use shade 200 for default, and keep all other shades the same
     });
+})
+
+.config(function($locationProvider) {
+  $locationProvider.hashPrefix('!');
 });