XMLUtil serializes DateProperties badly

[bshepherdson]

Feeding it any date results in:

<property name="birthday">  <object>
    <property name="toRelativeDateString">function toRelativeDateString(){
      var seconds = Math.floor((Date.now() - this.getTime())/1000);

      if ( seconds &lt; 60 ) return 'moments ago';

      var minutes = Math.floor((seconds)/60);

      if ( minutes == 1 ) return '1 minute ago';

      if ( minutes &lt; 60 ) return minutes + ' minutes ago';

      var hours = Math.floor(minutes/60);
      if ( hours == 1 ) return '1 hour ago';

      if ( hours &lt; 24 ) return hours + ' hours ago';

      var days = Math.floor(hours / 24);
      if ( days == 1 ) return '1 day ago';

      if ( days &lt; 7 ) return days + ' days ago';

      if ( days &lt; 365 ) {
        var year = 1900+this.getYear();
        var noyear = this.toDateString().replace(' ' + year, '');
        return noyear.substring(4);
      }

      return this.toDateString().substring(4);
    }
    </property>
    <property name="equals">function equals(o) {
      if ( ! o ) return false;
      if ( ! o.getTime ) return false;
      return this.getTime() === o.getTime();
    }
    </property>
    <property name="compareTo">function compareTo(o){
      if ( o === this ) return 0;
      if ( ! o ) return 1;
      var d = this.getTime() - o.getTime();
      return d == 0 ? 0 : d &gt; 0 ? 1 : -1;
    }
    </property>
    <property name="toMQL">function toMQL() {
      return this.getFullYear() + '/' + (this.getMonth() + 1) + '/' + this.getDate();
    }
    </property>
    <property name="toBQL">function toBQL() {
      var str = this.toISOString(); // eg. 2014-12-04T16:37:33.420Z
      return str.substring(0, str.indexOf('.')); // eg. 2014-12-04T16:37:33
    }
    </property>
  </object>
</property>