In a deep, medium skillet, melt the butter. Add the onion and ginger and cook over moderate heat, stirring occasionally, until softened, about 7 minutes. Add the curry powder and cook, stirring, for 1 minute. Add the chutney, cream cheese, mayonnaise and lime juice and cook, stirring, until smooth and creamy, about 1 minute. Stir in the scallions, cilantro and crab, breaking up the crab slightly with the spoon. Season with salt and pepper and cook until the dip is heated through, about 1 minute. Transfer to a shallow bowl and serve with chips.