Fixed building problems for iOS version

In this commit, I fixed the iOS project build errors introduced by #39 and some other commits.  I removed the USE_UNTZ preprocessor directive from the project file.  I also added the USE_UNTZ preprocessor directive as a condition for compiling the source of the UNTZ files.  In the case of `MOAIAppIOS`, `MOAIGameCenterIOS` and `MOAIMoviePlayerIOS`, I added back the destructor definitions that were removed by a commit that dealt with Automatic Resource Counting.