Added/Updated Podfile to address circular dependencies

Attempt to resolve this error on ```pod install``` and ```pod update``` with Cocoapods 0.35.0
```[!] There is a circular dependency between XMPPFramework/Core and XMPPFramework/Authentication```

- Manually add the latest Podfile from the official specs repo
- Initial attempt to remove circular dependencies
	- The 3rd party Podfile in the spec repo is maintained by a 3rd party, and aborts ```pod update``` ```pod install``` for version 0.35.0 of the ```pod``` gem.
	- This is due to the newly added dependency conflict auto-resolution
- This is a workaround to address issues breaking all update/installs for our project dependent on XMPPFramework.

The permanent solution to this is being addressed as part of:
https://github.com/CocoaPods/Molinillo/issues/6 - Initial ID of problem
https://github.com/CocoaPods/Specs/pull/12783 - Fixes, including XMPPFramework