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

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

Closes #400

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']);