revert(tabs): undo commit that removes tab sub pages

Fix advanced tabs test

This reverts
https://github.com/driftyco/ionic/commit/743de19ae898e83375b51ef9c376225
c8e63f0ef

src/config/config.ts

@@ -103,6 +103,7 @@ import { isObject, isDefined, isFunction, isArray } from '../util/util';
  * | `tabsHighlight`          | `boolean`           | Whether to show a highlight line under the tab when it is selected.                                                                              |
  * | `tabsLayout`             | `string`            | The layout to use for all tabs. Available options: `"icon-top"`, `"icon-left"`, `"icon-right"`, `"icon-bottom"`, `"icon-hide"`, `"title-hide"`.  |
  * | `tabsPlacement`          | `string`            | The position of the tabs relative to the content. Available options: `"top"`, `"bottom"`                                                         |
+ * | `tabsHideOnSubPages`     | `boolean`           | Whether to hide the tabs on child pages or not. If `true` it will not show the tabs on child pages.                                              |
  * | `toastEnter`             | `string`            | The name of the transition to use while a toast is presented.                                                                                    |
  * | `toastLeave`             | `string`            | The name of the transition to use while a toast is dismissed.                                                                                    |
  *

src/config/modes.ts

@@ -39,6 +39,7 @@ Config.setModeConfig('ios', {
 
   tabsHighlight: false,
   tabsPlacement: 'bottom',
+  tabsHideOnSubPages: false,
 
   toastEnter: 'toast-slide-in',
   toastLeave: 'toast-slide-out',
@@ -81,7 +82,8 @@ Config.setModeConfig('md', {
   spinner: 'crescent',
 
   tabsHighlight: true,
-  tabsPlacement: 'bottom',
+  tabsPlacement: 'top',
+  tabsHideOnSubPages: true,
 
   toastEnter: 'toast-md-slide-in',
   toastLeave: 'toast-md-slide-out',
@@ -125,6 +127,7 @@ Config.setModeConfig('wp', {
 
   tabsHighlight: false,
   tabsPlacement: 'top',
+  tabsHideOnSubPages: true,
 
   toastEnter: 'toast-wp-slide-in',
   toastLeave: 'toast-wp-slide-out',