Compatibility with Backbone.js 1.1.*

[janekbettinger]

I am not able to get backbone.d3 to work with the latest release of Backbone.js.
As from Backbone.js 1.1.0 I get an error in Underscore.js:

// Fill in a given object with default properties.
_.defaults = function(obj) {
  each(slice.call(arguments, 1), function(source) {
    if (source) {
      for (var prop in source) {
        // ERROR: obj is undefined (line 854 in Underscore.js 1.5.2; l. 881 in 1.6.0)
        if (obj[prop] === void 0) obj[prop] = source[prop];
      }
    }
  });
  return obj;
};

Unfortunately, I have not been capable to solve the problem on my own, yet.