Demo => Added switches for status bar and navigation bar visibility for testing

Updated demo app with toggle for the status bar visibility.

![ios simulator screen shot 8 may 2014 11 51 03 am](https://cloud.githubusercontent.com/assets/1650398/2911066/52c59a66-d653-11e3-93f9-992c68695baf.png)
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![ios simulator screen shot 8 may 2014 11 51 09 am](https://cloud.githubusercontent.com/assets/1650398/2911067/53edba9a-d653-11e3-8b1c-64dd1ac2b368.png)

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#63 #40