title: benign warning message in debug when compiling salesforce SDK app view controller stack
body: <p>I get a WARN message in the debug console, please note that the app does not fail, it runs fine however I am curious to know what the WARNing means: "WARN|SFRootViewManager|view controller ((null)) not found in the view controller stack.  No action taken."
  Any ideas what this means and what action I should take? I'm only worried (slightly) that this may have an affect later when I add more view controllers to the chain.</p>