Bullwhip Griffin
"Bullwhip Griffin" is a pleasant, low-key adventure comedy, good summer entertainment for youngsters and perhaps not too unlikely for their parents. If it isn't quite up to Walt Disney's best comedies ("The Absent-Minded Professor," for example), it is good Disney all the same, and many of the Disney trademarks are in evidence.The hero from the kid's point of view, I suspect, is Jack Flagg (Bryan Russell), an impossibly noble 12-year-old with blue eyes, scrubbed cheeks and the mature…