Heat the oil in a large pot over medium heat, and cook the onion until tender. Mix in the lentils and garlic, and season with curry powder, cumin, and cayenne pepper. Cook and stir 2 minutes. Stir in the tomatoes, garbanzo beans, kidney beans, and raisins. Season with salt and pepper. Reduce heat to low, and simmer at least 1 hour, stirring occasionally.