Adding youtube-ios-player-helper

Hey guys,

This is a toolkit we've created for our iOS developers who want to developer iOS applications that embed our iframe player in a UIWebView. This library does the work of translating between Objective-C and JavaScript. The source repo is here:

https://github.com/youtube/youtube-ios-player-helper

Let me know what else you guys need to get this into the central CocoaPods repository!

- Ikai Lan
ikai@google.com