registrationDictionaryByFillingInDictionary: Tries to fill in missing keys in a registration dictionary. This method examines the passed-in dictionary for missing keys, and tries to work out correct values for them. As of 0.7, it uses:
Key Value --- -----
Keys are only filled in if missing; if a key is present in the dictionary, its value will not be changed.
This method was introduced in Growl.framework 0.7.