title: Set default tab in ionic2
body: <p>On my login page I am using <code>this.nav.setRoot(TabsPage);</code> to navigate to the 'main app'. However, this makes the first tab the default page. On the other hand, if i use <code>this.nav.setRoot(HomePage)</code>; I get the correct page but am missing the tabs. How do I set the default tab on page switch?
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