Updated code to compile in XCode 6

When I originally cloned the repository, the project would not compile. I made several edits both to fix the errors and to improve the UI. There are no drastic UI changes, but they do adhere to current iOS 8 standards.

I compiled the code in hard-mode, so the code is now free of all errors. But, there are some test cases I commented out because I couldn't figure out how to fix them.

I spent a lot of time on this because I'm using this repository as a base for an app as well as a mechanism for teaching some of my coworkers persistence in iOS.