iOS8 updates

* Make possible to run Example app using Xcode 6
* Rerun `pod install` with the latest CocoaPods
* Put CocoaPods into Gemfile
* Remove all pods added for testing because they were not actually used.
* Upgrade test target to use XCTest instead of SenTesting
* Fix a deprecation warning - use `preferredContentSize` instead of `contentSizeForViewInPopover` on iOS7
* Alert the user if no camera access