message: Define property toJSON because just assigning it throws an error in Node 4
diff: @@ -53,7 +53,8 @@ FeathersError.prototype = new Error();
  // NOTE (EK): A little hack to get around `message` not
  // being included in the default toJSON call.
  -FeathersError.prototype.toJSON = function () {
  +Object.defineProperty(FeathersError.prototype, 'toJSON', {
  + value: function () {
  return {
  name: this.name,
  message: this.message,
  @@ -62,7 +63,8 @@ FeathersError.prototype.toJSON = function () {
  data: this.data,
  errors: this.errors
  };
  -};
  + }
  +});
  // 400 - Bad Request
  function BadRequest (message, data) {
  