Updated podspec for 5.0

The pod wasn't listed as an OSX cocoa pod.
![screen shot 2013-07-01 at 2 17 47 pm](https://f.cloud.github.com/assets/627285/730072/bb9493ee-e248-11e2-847a-481328a4ebaa.png)

After updating and pushing to cocoapods, works properly
![screen shot 2013-07-01 at 2 18 14 pm](https://f.cloud.github.com/assets/627285/730076/c6ae27ae-e248-11e2-83dc-be5453e540db.png)