Adds Kiwi Testing Examples

* Adds <code>CocoaPods</code> for library dependency management.
* Adds <code>CocoaLumberjack</code> logging framework.
* Adds <code>Kiwi</code> testing framework.
* Adds sample spec from <code>Kiwi</code> project.
* Rewrites <code>BrowseOverflowAppDelegateTests</code> using <code>Kiwi</code>.