SocketRocket framework on OSX 10.7

I'm using the FayeObjC library, which has a dependency on the SocketRocket OSX framework. 

After a recent upgrade of FayeObjC, our project stopped working on 10.7 with the following error:

```
dyld: Library not loaded: /System/Library/Frameworks/CFNetwork.framework/Versions/A/CFNetwork
  Referenced from: /Applications/TroupeNotifier Beta.app/Contents/MacOS/../Frameworks/SocketRocket.framework/Versions/A/SocketRocket
  Reason: image not found
Trace/BPT trap: 5
```

A quick search seems to indicate that CFNetwork is found at `/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CFNetwork.framework/CFNetwork` on 10.7. I found that by switching the Base SDK for the SocketRocketOSX famework from "`Latest OSX`" to "`10.7`" seems to fix the problem.

I'm not sure if this is the best way to fix this problem - if there's a better way please let me know. 

Thanks for an incredible useful library!