docs(typeahead): add async version of the demo

Author: matiboy

src/typeahead/docs/demo.html

@@ -1,4 +1,11 @@
 <div class='container-fluid' ng-controller="TypeaheadCtrl">
+
+    <h4>Static arrays</h4>
     <pre>Model: {{selected| json}}</pre>
     <input type="text" ng-model="selected" typeahead="state for state in states | filter:$viewValue | limitTo:8">
-</div>
+
+    <h4>Asynchronous results</h4>
+    <pre>Asynchronous values model: {{asyncSelected| json}}</pre>
+    <input type="text" ng-model="asyncSelected" placeholder="Locations loaded via $http" typeahead="address for address in getLocation($viewValue) | filter:$viewValue" typeahead-loading="loadingLocations">
+    <i ng-show="loadingLocations" class="icon-refresh"></i>
+</div>

src/typeahead/docs/demo.js

@@ -1,5 +1,20 @@
-function TypeaheadCtrl($scope) {
+function TypeaheadCtrl($scope, $http) {
 
   $scope.selected = undefined;
   $scope.states = ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware', 'Florida', 'Georgia', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico', 'New York', 'North Dakota', 'North Carolina', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania', 'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'];
-}
+  // Any function returning a promise object can be used to load values asynchronously
+  $scope.getLocation = function(val) {
+    return $http.get('http://maps.googleapis.com/maps/api/geocode/json', {
+      params: {
+        address: val,
+        sensor: false
+      }
+    }).then(function(res){
+      var addresses = [];
+      angular.forEach(res.data.results, function(item){
+        addresses.push(item.formatted_address);
+      });
+      return addresses;
+    });
+  };
+}