Make xctool compatible with Xcode 5.1

- Use DTiPhoneSimulatorRemoteClient instead of iPhoneSimulatorRemoteClient (by @fpotter)
- Add -destination (not multiple support yet) and -destination-timeout options support (by @fpotter and @ExtremeMan)
- Use -destination argument to launch iOS simulator: supports device name and OS version keys (by @ExtremeMan)