Make _.result call methods with surplus arguments

This pull request adds a small feature to `_.result`; when called with more than two arguments, those arguments are passed to an eventual method on the object:

    var obj = {method:someFunc, prop:"val"};
    _.result(obj,"method",1,2,3); // => returns result from calling someFunc(1,2,3) with obj as context
    _.result(obj,"prop",1,2,3); // => returns "val" like before, surplus args 1,2,3 have no effect