Add RRClass too in the RRsetCollection key, and make find() search for them
This commit also changes the base class's find() prototype to include the RRClass as an argument. Otherwise, we don't know what RRClass to look for. The arguments for the base class's find() method are in a different order from those of the find() methods in the RRsetCollection implementation as there's no way to overload the method when only its return value is different.
Showing with 29 additions and 19 deletions