Add support for iOS 7.1

iPhoneSimulatorRemoteClient got renamed to DVTiPhoneSimulatorRemoteClient.framework and introduced some changes. This PR addresses them.

The project was also converted to ARC from garbage collection and made compilable under Xcode 5.1. I haven't bumped the deployment target all the way to OS X 10.9, because more issues come with it, like strong-to-strong NSMapTable being deprecated (and NSTask not conforming to NSCopying).

The fix is heavily based on how [ios-sim](https://github.com/phonegap/ios-sim) uses the private framework to run the simulator: https://github.com/phonegap/ios-sim/blob/1.9.0/Source/iPhoneSimulator.m