NavigationView handles checked status

NavigationView now handles checked status in its menu. This was
necessary to handle checked status for items in sub menu. Also, it now
forces only one item to be marked as checked among all the checkable
items in the menu. Menu groups can be marked as checkedBehavior="single"
or ="all", but all the items behave the same in either cases.

Change-Id: Ia2e1a39475175b5ada8ec84273a39b995ec414c3
diff --git a/design/api/current.txt b/design/api/current.txt
index e0e49ea..4e71e40 100644
--- a/design/api/current.txt
+++ b/design/api/current.txt
@@ -197,6 +197,7 @@
     method public void setItemIconTintList(android.content.res.ColorStateList);
     method public void setItemTextColor(android.content.res.ColorStateList);
     method public void setNavigationItemSelectedListener(android.support.design.widget.NavigationView.OnNavigationItemSelectedListener);
+    method public void setCheckedItem(int);
   }
 
   public static abstract interface NavigationView.OnNavigationItemSelectedListener {