At first glance, flyfishing might appear to be the apex where drably dressed anglers, a long graphite wand, a small tuft of feather and fur, tumbling cold water and a hungry trout all intersect at a point in time.Call it genteel sport with the symphony warming up in the background.For extreme sports pioneer Greta Gaines, however, flyfishing is a sport that is ?? well, it is extreme.Forget the walk