feat($sniffer): basic implementation of browser feature testing

This only extracts our 'hashchange' event and html5 history api detection from
$browser.

Closes #400

src/AngularPublic.js

@@ -2,15 +2,14 @@
 
 var browserSingleton;
 
-angularService('$browser', function($log){
+angularService('$browser', function($log, $sniffer) {
   if (!browserSingleton) {
-    // TODO(vojta): inject $sniffer service when implemented
     browserSingleton = new Browser(window, jqLite(window.document), jqLite(window.document.body),
-                                   XHR, $log, {});
+                                   XHR, $log, $sniffer);
     browserSingleton.bind();
   }
   return browserSingleton;
-}, {$inject:['$log']});
+}, {$inject: ['$log', '$sniffer']});
 
 
 extend(angular, {

src/angular-bootstrap.js

@@ -115,6 +115,7 @@
              'service/resource.js',
              'service/route.js',
              'service/routeParams.js',
+             'service/sniffer.js',
              'service/window.js',
              'service/xhr.bulk.js',
              'service/xhr.cache.js',

src/service/sniffer.js

@@ -0,0 +1,24 @@
+'use strict';
+
+/**
+ * @workInProgress
+ * @ngdoc service
+ * @name angular.service.$sniffer
+ * @requires $window
+ *
+ * @property {boolean} history Does the browser support html5 history api ?
+ * @property {boolean} hashchange Does the browser support hashchange event ?
+ *
+ * @description
+ * This is very simple implementation of testing browser's features.
+ */
+angularServiceInject('$sniffer', function($window) {
+  if ($window.Modernizr) return $window.Modernizr;
+
+  return {
+    history: !!($window.history && $window.history.pushState),
+    hashchange: 'onhashchange' in $window &&
+                // IE8 compatible mode lies
+                (!$window.document.documentMode || $window.document.documentMode > 7)
+  };
+}, ['$window']);