demo($ionicLoading): add basic demo

js/angular/service/loading.js

@@ -30,6 +30,53 @@ var LOADING_SET_DEPRECATED = '$ionicLoading instance.setContent() has been depre
  * });
  * ```
  */
+/**
+ * @ngdoc demo
+ * @name $ionicLoading#loadThemAll
+ * @module loadingThemAll
+ * @javascript
+ * angular.module('loadingThemAll', ['ionic'])
+ * .controller('LoadingCtrl', function($scope, $ionicLoading) {
+ *   $scope.loadingOptions = {
+ *     duration: 1000,
+ *     delay: 0,
+ *     template: '<i class="icon ion-loading-c"></i>\n<br/>\nLoading...',
+ *     noBackdrop: false
+ *   };
+ *   $scope.showLoading = function() {
+ *     $ionicLoading.show($scope.loadingOptions);
+ *   };
+ * });
+ * @html
+ * <div ng-controller="LoadingCtrl">
+ *   <ion-header-bar class="bar-positive">
+ *     <h1 class="title">Loading Demo</h1>
+ *     <a class="button" ng-click="showLoading()">
+ *       <i class="icon ion-more"></i> Load
+ *     </a>
+ *   </ion-header-bar>
+ *   <ion-content>
+ *     <div class="list">
+ *       <label class="item item-input item-stacked-label">
+ *         <span class="input-label">Loading Duration (ms)</span>
+ *         <input type="number" ng-model="loadingOptions.duration">
+ *       </label>
+ *       <label class="item item-input item-stacked-label">
+ *         <span class="input-label">Loading Delay (ms)</span>
+ *         <input type="number" ng-model="loadingOptions.delay">
+ *       </label>
+ *       <label class="item item-input item-stacked-label">
+ *         <span class="input-label">Loading Template</span>
+ *         <textarea rows="3" ng-model="loadingOptions.template"></textarea>
+ *       </label>
+ *       <ion-toggle class="item item-toggle"
+ *                   ng-model="loadingOptions.noBackdrop">
+ *         Hide Backdrop?
+ *       </ion-toggle>
+ *     </div>
+ *   </ion-content>
+ * </div>
+ */
 IonicModule
 .factory('$ionicLoading', [
   '$document',