Added display of NSLogs

Thanks for sharing your debug widget!

I've added a feature where it will now display 'NSLog' calls inside of it after 'enableLogging' is called and thought you may like to merge it. Please review and see if its of interest.

Thanks

![screen shot 2014-04-02 at 15 06 04](https://cloud.githubusercontent.com/assets/2040617/2592230/5b166eda-ba73-11e3-9f87-0a8ce00ad263.png)