Migrate launcher project to ARC

ARC is strongly encouraged by Apple for new project *

In order to facilitate the integration of the Readium reader in new iOS project the launcher project itself should use ARC 


*http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/MemoryMgmt/Articles/MemoryMgmt.html#//apple_ref/doc/uid/10000011i