Added implementation.

Problem as this stands is that it references the existing CocoaPod which is
prior to the namespace change from PK to RPK.  On iOS 8, this results in a
run-time warning:

objc[1927]: Class PKManager is implemented in both /System/Library/PrivateFrameworks/PlugInKit.framework/PlugInKit and /private/var/mobile/Containers/Bundle/Application/EEA746BA-574B-45DF-8A2D-68DC928FCAB4/SwiftBeacon.app/SwiftBeacon. One of the two will be used. Which one is undefined.
objc[1927]: Class PKRegion is implemented in both /System/Library/PrivateFrameworks/PhysicsKit.framework/PhysicsKit and /private/var/mobile/Containers/Bundle/Application/EEA746BA-574B-45DF-8A2D-68DC928FCAB4/SwiftBeacon.app/SwiftBeacon. One of the two will be used. Which one is undefined.

These are causing me grief, as the code that used to work (probably prior to my
iOS 8 update but after Swift became available) no longer works on my phone.