refactor: remove short imports of modules from tns-core-modules (#1550)

The tests should be updated as well.

party resolves #1535

Author: sis0k0

nativescript-angular/directives/action-bar.ts

@@ -82,9 +82,9 @@ const appendActionItem = (bar: NgActionBar, item: ActionItem) => {
     bar.actionItems.addItem(item);
 };
 
-registerElement("ActionBar", () => require("ui/action-bar").ActionBar, actionBarMeta);
-registerElement("ActionItem", () => require("ui/action-bar").ActionItem);
-registerElement("NavigationButton", () => require("ui/action-bar").NavigationButton);
+registerElement("ActionBar", () => require("tns-core-modules/ui/action-bar").ActionBar, actionBarMeta);
+registerElement("ActionItem", () => require("tns-core-modules/ui/action-bar").ActionItem);
+registerElement("NavigationButton", () => require("tns-core-modules/ui/action-bar").NavigationButton);
 
 @Component({
     selector: "ActionBar",