Management of Finder tags and other improvements

- Added NSThread.CallStackSymbols method
- Created module ObjcRuntime which will define the C-level Objective-C Runtime functions.
- Extended NotificationObserver so it can observe Distributed Notifications too.
- Added getting/setting the new Mavericks Tags in NSURL and as an extension of FolderItem.
- Added SystemFinderTags and SystemFinderTagColors to the SystemExtensions module as a workaround to get Finder tags and their corresponding color.
- Improved DebugReports to properly handle Colors and array of Colors with or without alpha channel.
- The QuickStart window now makes the difference between a brand new user and someone who already ran macoslib and set the default message/button accordingly.