Added CSRF support.

[oal]

I don't know if this is what you had in mind when it comes to CSRF support, but this solution works well for me. You simply specify "csrf: 'sometoken'" in Options, like this:

var client = new $.RestClient('/api/v1/', {
    csrf: '{{ csrftoken }}'
});

And the token is sent along with all requests using the X-CSRFToken header.

Feel free to pull, or ignore if you have plans for a different approach.

[curtailment]

Simple and easy to use fix. The only issue I see is that the header name is hard-coded. I suggest including a way to change this (for example, Laravel 5 uses X-CSRF-TOKEN). Although since this pull hasn't been resolved after a year, I would recommend people do something like the following:

$.ajaxSetup({
        headers: {
            'X-CSRF-TOKEN': 'mytokenhere'
        }
});

Warning: this will add the token to all ajax requests, not just those made by this library.