Can pass extra arguments to onResourceRequested which runs in phantomjs scope

Currently, it is impossible to pass any arguments to the first arguments of `page.onResourceRequested`.

With this commit, when we define `page.onResourceRequested`, we can pass more than 2 arguments to the function, the extra ones(from the 3rd) will be passed to the function which can access `request.abort()` as the extra parameters.

The code should look like:
```
page.onResourceRequested(
    function(requestData, request, arg1, arg2, arg3) {
        request.abort();
        console.log(arg1, arg2, arg3); //success! 
    },
    function(requestData) { },
    arg1, arg2, arg3
);
```

BTW, this won't break any existing code.