fix(nav): start zIndex at 10

ionic/components/item/item.scss

@@ -30,8 +30,8 @@
   min-height: 30px;
   font-weight: 500;
   width: 100%;
-  z-index: 100;
   z-index: 1000;
+  
   &.sticky {
     position: -webkit-sticky;
     position: sticky;

ionic/components/nav/nav-controller.ts

@@ -579,7 +579,7 @@ export class NavController extends Ion {
 
   _setZIndex(enteringInstance, leavingInstance, direction) {
     if (!leavingInstance) {
-      enteringInstance._zIndex = 0;
+      enteringInstance._zIndex = 10;
 
     } else if (direction === 'back') {
       // moving back

ionic/components/nav/test/nav-controller.spec.ts

@@ -1,20 +1,3 @@
-// import {
-//   ddescribe,
-//   describe,
-//   xdescribe,
-//   it,
-//   iit,
-//   xit,
-//   expect,
-//   beforeEach,
-//   afterEach,
-//   AsyncTestCompleter,
-//   inject,
-//   beforeEachBindings
-// } from 'angular2/test';
-
-// import {Compiler} from 'angular2/angular2';
-
 import {
   NavController,
   Config,