Open Terminal in OSX
	Enter the command:    cd music/itunes/"mobile applications"
	Enter the command:   ls
	You should see Doom.ipa listed.  If not then you need to make sure that Doom is backed up to your iTunes Library
	Enter the command:   cp Doom.ipa Doom.zip
	This copies and renames your iTunes backup of Doom
	Open Finder
	Go to the folder:   /Users/username/Music/iTunes/Mobile Applications/   (where "username" is your username)
	You should see Doom.zip listed
	Double click Doom.zip to uncompress
	Navigate to the new folder (should be named "Payload")
	Right click on Doom.app and choose "Show Package Contents"
	This will open a new Finder displaying the contents of Doom.app
	Copy the base folder
	Paste the base folder in the DoomSource folder
	Open  the Doom xcode project located at ../DoomSource/code/iphone/Doom.xcodeproj
	Click on "Build and Go" or press "command + R" to build and then run Doom