Callback lifetimes

[jwharm]

Handle the scope attribute of callback parameters to manage memory allocated by Java-GI for the upcall-stub of the callback function. The following scenarios are supported:

• Callback is deallocated directly after the function call (try-with-resources block)
• Callback is deallocated when the instance is garbage-collected (for instance methods with callback parameters)
• Callback is deallocated by a GDestroyNotify closure (notified scope in the gir file)
• Callback is not deallocated until the application quits