allow the adding of a user object to the Appointment

[GoogleCodeExporter]

Description of the new feature:
The product would benefit from the ability to associate a user object with an 
appointment. Similar to the feature provided by GWT and Swing trees, the user 
would be able to add their own user object to the gwt-cal Appointment object.


Assumptions:
1. The user has an object that is associated with an appointment.

Exceptions:
1.
2.
3.

Code / psuedo-code:
calendar.suspendLayout();
for (DTOProjectTast dtoProjectTask : listOfDTOProjectTask) {
   Appointment appointment = new Appointment();
   appointment.setUserObject(dtoProjectTask);
   ...
}
calendar.resumeLayout();

Original issue reported on code.google.com by roderick...@gmail.com on 29 Jul 2013 at 11:02