Merge pull request #185 from zacronos/digest-in-progress-fix

@zacronos Thanks! I'm going to merge it right now, but it needs to be further investigated.

In addition I would like to say that we already have something on that score, I mean the scroll event handler. And you don't see [there](https://github.com/angular-ui/ui-scroll/blob/v1.7.0-rc.2/src/ui-scroll.js#L437) a `!$rootScope.$$phase` protection due to it is present in the [beginning](https://github.com/angular-ui/ui-scroll/blob/v1.7.0-rc.2/src/ui-scroll.js#L429) of function.

Author: dhilt

src/ui-scroll.js

@@ -349,7 +349,7 @@ angular.module('ui.scroll', [])
           let updates = updateDOM();
 
           // We need the item bindings to be processed before we can do adjustment
-          !$scope.$$phase && $scope.$digest();
+          !$scope.$$phase && !$scope.$root.$$phase && $scope.$digest();
 
           updates.inserted.forEach(w => w.element.removeClass('ng-hide'));
           updates.prepended.forEach(w => w.element.removeClass('ng-hide'));
@@ -370,7 +370,7 @@ angular.module('ui.scroll', [])
           let updates = updateDOM();
 
           // We need the item bindings to be processed before we can do adjustment
-          !$scope.$$phase && $scope.$digest();
+          !$scope.$$phase && !$scope.$root.$$phase && $scope.$digest();
 
           updates.inserted.forEach(w => w.element.removeClass('ng-hide'));
           updates.prepended.forEach(w => w.element.removeClass('ng-hide'));