Added HockeyApp SDK for internal builds

* Add the HockeyApp SDK to CocoaPods
* HockeyApp App ID added to the external configuration & incorporated into the Ruby script to build the credentials file
* Force HockeyApp to request device UDID authorization through a pop-out to HockeyApp's site - requires web clip to be installed (which it should be)
* Alerts users to new versions being available

This will add to the binary size for production since we can't conditionally exclude (I believe) the HockeyApp library from the binary.  That was my original intention for having a separate target for the Internal build to be able to change libraries around in CocoaPods.